Update merge request sticky header title on draft status change

What does this MR do and why?

Updates the merge requests sticky header title whenever the merge requests draft status gets changed.

Screenshots or screen recordings

• Enable realtime_mr_status_change feature flag

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

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.