The code paths that used to use these locks have been long removed so we
can safely remove them. Additionally these are superceded by better
de-duplication mechanisms including sidekiq queue de-duplication for
`ElasticCommitIndexerWorker`, redis sorted sets for other indexing jobs
and finally we added a lock inside of `ElasticCommitIndexerWorker`
recently to avoid a related problem that these locks didn't even cover
anyway https://gitlab.com/gitlab-org/gitlab/-/merge_requests/35842 .