Add new merge trains link

Payton Burdetterequested to merge
469149-new-merge-trains-link into master

What does this MR do and why?

Adds a new merge trains button to the merge requests list view.

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

Screenshot_2024-07-25_at_11.11.45_AM

How to set up and validate locally

  1. Visit Project > Code > Merge requests
  2. Click Merge trains

Related to #469149 (closed)

Merge request reports