Add key unbinds to DiscussionKeyboardNavigator
What does this MR do?
Addresses the comment here https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30144#note_204050258 by adding key unbinds on component destroy as well as a helpful comment.
Does this MR meet the acceptance criteria?
Conformity
-
Changelog entry for user-facing changes, or community contribution. Check the link for other scenarios. -
Documentation created/updated or follow-up review issue created -
Code review guidelines -
Merge request performance guidelines -
Style guides -
Database guides -
Separation of EE specific content