Add sort runners on admin runners

What does this MR do?

Add sort runners by last contacted on admin runners.

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

No.

Why was this MR needed?

Admins want to clean up inactive ones from dozens of the registered runners. For that, sort runners by 'Last contacted' on admin runners would be helpful.

(from #38720)

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [n/a] Documentation created/updated
• [n/a] API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together

What are the relevant issue numbers?

Closes #38720