Add copy permalink to repository overflow menu

What does this MR do and why?

This MR adds the new copy permalink item to the repository overflow menu. This feature currently only exists on blob page.

References

Please include cross links to any resources that are relevant to this MR. This will give reviewers and future readers helpful context to give an efficient review of the changes introduced.

• Component was added in !181901 (merged)
• ⚠️ there is a bug with shortcut not working, when navigating from repository page. it's being addressed in !183768 (merged)
• See #452305 (comment 2347171106) for technical discussion on copied path

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

CleanShot 2025-03-07 at 16.15.21.mp4

Flow	Expected Url
At project overview	https://gdk.test:3443/gitlab-org/gitlab-shell
With branch	https://gdk.test:3443/gitlab-org/gitlab-shell/-/tree/id-update-golang/.gitlab?ref_type=heads
With tag	https://gdk.test:3443/gitlab-org/gitlab-shell/-/tree/v14.40.0/.gitlab?ref_type=tags
With commit	https://gdk.test:3443/gitlab-org/gitlab-shell/-/tree/8e902346d14531b6da1552b948f206f0fec8da73/doc

How to set up and validate locally

1. Enable blob_overflow_menu and enable blob_repository_vue_header_app feature flag

   Feature.enable(:blob_overflow_menu)
   Feature.enable(:blob_repository_vue_header_app)

• Go to a directory
  • This should work when viewing with:
    1. A branch
    2. A commit (Code > Repository > Commits > Brows files (folder icon)
    3. A tag
  • Press y should work the same as clicking the dropdown item

Related to #452305 (closed)