Issue 22424: Add tooltip to header of Done list

What does this MR do?

Adds a tooltip to the Done board per this issue

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

Why was this MR needed?

Screenshots (if relevant)

before:

after:

Does this MR meet the acceptance criteria?

I left certain items that were n/a blank (docs/api/test). The MR is ready for merge.

• Changelog entry added, if necessary
• n/a Documentation created/updated
• n/a API support added
• Tests
  • n/a Added for this feature/bug
  • All builds are passing
• n/a Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Closes #22424 (closed)