Stop attributing system events to users in merge requests when action was done by the system
<!--IssueSummary start-->
<details>
<summary>
Everyone can contribute. [Help move this issue forward](https://handbook.gitlab.com/handbook/marketing/developer-relations/contributor-success/community-contributors-workflows/#contributor-links) while earning points, leveling up and collecting rewards.
</summary>
- [Close this issue](https://contributors.gitlab.com/manage-issue?action=close&projectId=278964&issueIid=368800)
</details>
<!--IssueSummary end-->
<!-- The first section "Release notes" is required if you want to have your release post blog MR auto generated. Currently in BETA, details on the **release post item generator** can be found in the handbook: https://about.gitlab.com/handbook/marketing/blog/release-posts/#release-post-item-generator and this video: https://www.youtube.com/watch?v=rfn9ebgTwKg. The next four sections: "Problem to solve", "Intended users", "User experience goal", and "Proposal", are strongly recommended in your first draft, while the rest of the sections can be filled out during the problem validation or breakdown phase. However, keep in mind that providing complete and relevant information early helps our product team validate the problem and start working on a solution. -->
### Proposal
Use `GitLab` in place of a user name when it is a system event not initiated by the user. This would be a plain text without a link.
{width=819 height=124}
Discussion around proposed solution https://gitlab.com/gitlab-org/gitlab/-/issues/368800#note_3010823752.
Ideal solution would be to have specific sentences for this scenario https://gitlab.com/gitlab-org/gitlab/-/issues/368800#note_3009945117
### Problem to solve
In the MRs, for some actions that are performed by the system, such as drop/cancel an MR from a train, are attributed to users. This leaves the users misinformed and in most instances very confused and thinking what did they do to make the train drop the MR. This is one event that I as an author of this issue am aware of, there might be more.
Screenshot from a gitaly MR: https://gitlab.com/gitlab-org/gitaly/-/merge_requests/2680

<!-- What problem do we solve? Try to define the who/what/why of the opportunity as a user story. For example, "As a (who), I want (what), so I can (why/value)." -->
### Intended users
All personas interacting with MRs would be affected.
### User experience goal
The activity log should correctly communicate to users if an event was performed by the system.
<!-- What is the single user experience workflow this problem addresses?
For example, "The user should be able to use the UI/API/.gitlab-ci.yml with GitLab to <perform a specific task>"
https://about.gitlab.com/handbook/engineering/ux/ux-research-training/user-story-mapping/ -->
<!-- How are we going to solve the problem? Try to include the user journey! https://about.gitlab.com/handbook/journeys/#user-journey -->
### Further details
<!-- Include use cases, benefits, goals, or any other details that will help us understand the problem better. -->
### Permissions and Security
<!-- What permissions are required to perform the described actions? Are they consistent with the existing permissions as documented for users, groups, and projects as appropriate? Is the proposed behavior consistent between the UI, API, and other access methods (e.g. email replies)?
Consider adding checkboxes and expectations of users with certain levels of membership https://docs.gitlab.com/ee/user/permissions.html
* [ ] Add expected impact to members with no access (0)
* [ ] Add expected impact to Guest (10) members
* [ ] Add expected impact to Reporter (20) members
* [ ] Add expected impact to Developer (30) members
* [ ] Add expected impact to Maintainer (40) members
* [ ] Add expected impact to Owner (50) members
Please consider performing a threat model for the code changes that are introduced as part of this feature. To get started, refer to our Threat Modeling handbook page https://about.gitlab.com/handbook/security/threat_modeling/#threat-modeling.
Don't hesitate to reach out to the Application Security Team (`@gitlab-com/gl-security/appsec`) to discuss any security concerns.
-->
### Documentation
<!-- See the Feature Change Documentation Workflow https://docs.gitlab.com/ee/development/documentation/workflow.html#for-a-product-change
* Add all known Documentation Requirements in this section. See https://docs.gitlab.com/ee/development/documentation/workflow.html
* If this feature requires changing permissions, update the permissions document. See https://docs.gitlab.com/ee/user/permissions.html -->
### Availability & Testing
<!-- This section needs to be retained and filled in during the workflow planning breakdown phase of this feature proposal, if not earlier.
What risks does this change pose to our availability? How might it affect the quality of the product? What additional test coverage or changes to tests will be needed? Will it require cross-browser testing?
Please list the test areas (unit, integration and end-to-end) that needs to be added or updated to ensure that this feature will work as intended. Please use the list below as guidance.
* Unit test changes
* Integration test changes
* End-to-end test change
See the Quality Engineering quad planning and test planning processes and reach out to your counterpart Software Engineer in Test for assistance.
Quad Planning: https://about.gitlab.com/handbook/engineering/quality/quality-engineering/quad-planning
Test Planning: https://about.gitlab.com/handbook/engineering/quality/quality-engineering/test-engineering/#test-planning -->
### Available Tier
Free
### Feature Usage Metrics
<!-- How are you going to track usage of this feature? Think about user behavior and their interaction with the product. What indicates someone is getting value from it?
Create tracking issue using the Snowplow event tracking template. See https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Snowplow%20event%20tracking.md
-->
### What does success look like, and how can we measure that?
<!--
Define both the success metrics and acceptance criteria. Note that success metrics indicate the desired business outcomes, while acceptance criteria indicate when the solution is working correctly. If there is no way to measure success, link to an issue that will implement a way to measure this.
Create tracking issue using the Snowplow event tracking template. See https://gitlab.com/gitlab-org/gitlab/-/blob/master/.gitlab/issue_templates/Snowplow%20event%20tracking.md
-->
### What is the type of buyer?
<!-- What is the buyer persona for this feature? See https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/buyer-persona/
In which enterprise tier should this feature go? See https://about.gitlab.com/handbook/product/pricing/#three-tiers -->
### Is this a cross-stage feature?
Yes, with ~"group::pipeline execution".
<!-- Communicate if this change will affect multiple Stage Groups or product areas. We recommend always start with the assumption that a feature request will have an impact into another Group. Loop in the most relevant PM and Product Designer from that Group to provide strategic support to help align the Group's broader plan and vision, as well as to avoid UX and technical debt. https://about.gitlab.com/handbook/product/#cross-stage-features -->
### What is the competitive advantage or differentiation for this feature?
### Links / references
<!-- Label reminders - you should have one of each of the following labels.
Use the following resources to find the appropriate labels:
- https://gitlab.com/gitlab-org/gitlab/-/labels
- https://about.gitlab.com/handbook/product/categories/features/
-->
<!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->
*This page may contain information related to upcoming products, features and functionality.
It is important to note that the information presented is for informational purposes only, so please do not rely on the information for purchasing or planning purposes.
Just like with all projects, the items mentioned on the page are subject to change or delay, and the development, release, and timing of any products, features, or functionality remain at the sole discretion of GitLab Inc.*
<!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->
issue