Removing list labels on closing an issue

What does this MR do?

Removes list labels associated with an issue on close of the issue.

Why was this MR needed?

Currently the list(board) labels for an issue only get removed if the issue is closed from the boards page. If someone closes the issue either directly from the issue page or the issue gets closed automatically, the board labels remain which is confusing.

Screenshots (if relevant)

Before After

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

What are the relevant issue numbers?

#29277 (moved)

Closes #29277 (moved)