Fix error when creating labels in a new issue in the boards page
What does this MR do?
This MR fixes a problem when adding labels to a newly created issue from the boards page (more info in the linked issue).
After some debugging I found out we weren't adding
assignableLabelsEndpoint to the issue after creating it like we do with some other values so the
data-labels attribute wasn't added.
What are the relevant issue numbers?
Does this MR meet the acceptance criteria?
- Changelog entry added, if necessary
- Documentation created/updated
- Tests added for this feature/bug
- Tested in all supported browsers
- Conforms to the code review guidelines
- Conforms to the merge request performance guidelines
- Conforms to the style guides
- Conforms to the database guides
- Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
- Security reports checked/validated by reviewer
Closes #54311 (closed)