Merge branch '441536-remove-ff-exclusive-lease' into 'master'

Remove FF `do_not_use_exclusive_lease_for_user_activity_service`

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/152168



Merged-by: Doug Stull <dstull@gitlab.com>
Approved-by: Doug Stull <dstull@gitlab.com>
Co-authored-by: Manoj M J <mmj@gitlab.com>