Remove the fetch_mirror_check_tags_changed feature flag

changelogs/unreleased/292602-remove-fetch_mirror_check_tags_changed-ff.yml

+---
+title: Improve pull mirroring performance
+merge_request: 54353
+author:
+type: performance

ee/app/services/projects/update_mirror_service.rb

@@ -33,7 +33,7 @@ module Projects
       checksum_before = project.repository.checksum
 
       update_tags do
-        project.fetch_mirror(forced: true, check_tags_changed: Feature.enabled?(:fetch_mirror_check_tags_changed, project))
+        project.fetch_mirror(forced: true, check_tags_changed: true)
       end
 
       update_branches

ee/config/feature_flags/development/fetch_mirror_check_tags_changed.yml

----
-name: fetch_mirror_check_tags_changed
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/49629
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/292602
-milestone: '13.8'
-type: development
-group: group::source code
-default_enabled: false