Terraform MR widget UI polish

What does this MR do and why?

The MR fixes UI issues:

• updates the color of the small text;
• fixes the position of the actions button.

Screenshots or screen recordings

Before	After

License Compliance Screenshots (screenshots added by @farias-gl as part of review)

How to set up and validate locally

1. Enable refactor_mr_widgets_extensions feature flag in rails console - Feature.enable(:refactor_mr_widgets_extensions)
2. Follow the docs. For the quick start:
   • you can clone the example repository
   • create personal token in settings
   • create a variable TF_VAR_gitlab_access_token with the token

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Review progress:

• UX review
• frontend developer review
• frontend maintainer review

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Related to #358740 (closed)