Merge branch 'tchu-cleanup-ff-code-for-search-vertical-nav-already-removed' into 'master'

Remove FF that was already removed

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/112090



Merged-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Tomas Vik <tvik@gitlab.com>
Co-authored-by: Terri Chu <tchu@gitlab.com>