Enable filtering MR list based on clicked label in MR sidebar

What does this MR do?

Fixes a long standing ~bug where clicking on label immediately after adding or removing labels in MR sidebar would take user to Issues list filtered by clicked label instead of MR list.

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [ ] Documentation created/updated
• [ ] 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
• [ ] Internationalization required/considered
• [ ] End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #43643 (closed)