Merge branch '470481-cleanup-sync-audit-events-to-new-tables-ff' into 'master'

Cleanup sync_audit_events_to_new_tables feature flag

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/161982



Merged-by: Aakriti Gupta <agupta@gitlab.com>
Approved-by: Hitesh Raghuvanshi <hraghuvanshi@gitlab.com>
Approved-by: Aakriti Gupta <agupta@gitlab.com>
Co-authored-by: harsimarsandhu <hsandhu@gitlab.com>