Implementation: Generate a commit SHA-specific chain of custody report [Frontend]
### Problem to solve
This is the ~frontend implementation issue for `Generate a commit SHA-specific chain of custody report` https://gitlab.com/groups/gitlab-org/-/epics/4608.
### User experience goal
An `administrator` or `group owner` input a specific commimt SHA into a [chain of custody](https://gitlab.com/gitlab-org/gitlab/-/issues/213364) download prompt and receive a CSV report in the same format, but which shows the MR, pipeline, author, approver, etc for that specific commit SHA.
### Intended users
* [Cameron (Compliance Manager)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#cameron-compliance-manager)
* [Delaney (Development Team Lead)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#delaney-development-team-lead)
* [Sasha (Software Developer)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sasha-software-developer)
* [Sidney (Systems Administrator)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#sidney-systems-administrator)
* [Rachel (Release Manager)](https://about.gitlab.com/handbook/marketing/product-marketing/roles-personas/#rachel-release-manager)
### Proposal
Update the [chain of custody report](https://gitlab.com/gitlab-org/gitlab/-/issues/213364) to filter the criteria to show only data points related to the specific commit SHA provided by a user.
1. An `admin` or `group owner` clicks on the `export` button and sees a prompt
1. Their options could be: `[List of all merge requests]` or `[ Search Commit SHA]`
1. Using the second option, they input `1a2bc3` to find a commit sha report
1. They receive the same report as we've built in https://gitlab.com/gitlab-org/gitlab/-/issues/213364, but it would show *only* data related to the specific commit SHA
| Empty State | Error | Long hash |
|-------------|-------|-----------|
|  |  |  |
### Implementation
1. Change the `List all merge commits` button to a [button with dropdown](https://design.gitlab.com/components/dropdowns/#button-combinations) with the new input form.
1. On input done, check if the hash is valid with a simple regular expression.
1. On export click, submit the commit hash to the `mergeCommitsCsvExportPath`.
issue