Migrate status checks to the merge request reports framework
## What is happening?
This epic is to track the engineering efforts of the status checks widget using the new [merge request reports framework](https://design.gitlab.com/regions/merge-request-reports).
### Required reading
- [Related UX Issue](https://gitlab.com/gitlab-org/gitlab/-/issues/336172)
- [Figma Design Specifications](https://www.figma.com/file/qEddyqCrI7kPSBjGmwkZzQ/Component-library?node-id=40674%3A48504)
- [Merge request reports framework](https://design.gitlab.com/regions/merge-request-reports)
- [Example: Load performance test metrics](https://gitlab.com/gitlab-org/ci-sample-projects/load-performance-testing-demo/-/merge_requests/1)
## Design screenshot

## Implementation issues
~frontend
Blockers that we need to resolve with the MR widget extension https://gitlab.com/groups/gitlab-org/-/epics/6647 before we can implement this feature:
- Add support for fetch failures https://gitlab.com/gitlab-org/gitlab/-/issues/345496 :two:
- Add support for hiding the dropdown
https://gitlab.com/gitlab-org/gitlab/-/issues/345497 :one:
- Add support for callbacks on tertiary button https://gitlab.com/gitlab-org/gitlab/-/issues/345498 :two:
Once those are resolve we can start work on migrating the status checks to the new framework by:
- Create status checks extension with the existing behaviour https://gitlab.com/gitlab-org/gitlab/-/issues/345502 :four:
- Add the ability to retry fetching the status checks reports on failure https://gitlab.com/gitlab-org/gitlab/-/issues/345253 :two:
Then there are also non-blocking bugs that we should resolve with the MR widget extension https://gitlab.com/groups/gitlab-org/-/epics/6647:
- The label is not vertically centered while loading https://gitlab.com/gitlab-org/gitlab/-/issues/345499 :one:
- The last row of the full report is not selectable https://gitlab.com/gitlab-org/gitlab/-/issues/345501 :one:
## Rollout plan
New widget extensions are hidden behind the existing `refactorMrWidgetsExtensions` (per project) and `refactorMrWidgetsExtensionsUser` (per user) feature flags. I think we should stay behind these feature flags since the new framework implementation https://gitlab.com/groups/gitlab-org/-/epics/6647 is still a work in progress.
~"feature flag" rollout issue: https://gitlab.com/gitlab-org/gitlab/-/issues/341759
epic