Add sticky header for work item drawer

What does this MR do and why?

Allow the work item sticky header to be shown when in a drawer, but conditionally apply some styles that make it behave as expected.

References

Screenshots or screen recordings

Before After
Screen_Recording_2025-07-30_at_17.07.24 Screen_Recording_2025-07-30_at_17.06.30

How to set up and validate locally

  1. Visit an isses list page in the GDK
  2. click a work item to open it in the drawer
  3. scroll the work item
  4. the sticky header with the work item's status, name, edit button, todo button, notification button and more options menu will appear, and stay in an absolute position while you scroll
  5. scroll back to the top of the work item
  6. the sticky header will disappear

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #520184 (closed)

Merge request reports

Loading