Related Issues UX improvements - loading

Merged username-removed-892863 requested to merge 33533-related-issues-ux-improvements into master

What does this MR do?

  • Move the loading icon into the panel body
  • Add transition when the panel body collapses away after fetching and the loading icon goes away
  • Add loading icon to the submit button
  • Server-side render basic panel heading for Related Issues as a placeholder until the JS kicks-in

Are there points in the code the reviewer needs to double check?

  • Do we want the loading spinner to be centered in the panel body?
    • The loadingIcon Vue component has text-center in it

Why was this MR needed?

Follow-up feedback to address,

Does this MR meet the acceptance criteria?

What are the relevant issue numbers?

Closes #33533

Edited by username-removed-892863