Add banner to the new Group Runners list

What does this MR do and why?

Fix for #354006 (closed)

This change adds a banner to take users to the new Group Runners list when the feature flag runner_list_group_view_vue_ui for the group is enabled.

Screenshots or screen recordings

Banner added

Expand/Collapse

How to set up and validate locally

1. Enable the new Group Runners page

   Feature.enable(:runner_list_group_view_vue_ui)

2. Visit CI/CD settings for a group http://gdk.test:3000/groups/h5bp/-/settings/ci_cd
3. Expand the "Runners" section
4. Check the banner, click on "Take me there!" to visit the new page

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.

Related to #354006 (closed)