Remove Danger rule that adds tags to MR title upon FF change

This usage of feature flag is now done statically, thanks to
https://gitlab.com/gitlab-org/gitlab/-/merge_requests/61052.
Signed-off-by: Rémy Coutable <remy@rymai.me>

danger/feature_flag/Dangerfile

@@ -68,27 +68,3 @@ end
 if helper.security_mr? && feature_flag_file_added?
   fail "Feature flags are discouraged from security merge requests. Read the [security documentation](https://gitlab.com/gitlab-org/release/docs/-/blob/master/general/security/utilities/feature_flags.md) for details."
 end
-
-if feature_flag_file_added_or_removed?
-  new_mr_title = helper.mr_title.dup
-  new_mr_title << ' [RUN ALL RSPEC]' unless helper.run_all_rspec_mr?
-  new_mr_title << ' [RUN AS-IF-FOSS]' unless helper.run_as_if_foss_mr?
-
-  changes = {}
-  changes[:add_labels] = FEATURE_FLAG_LABEL unless helper.mr_has_labels?(FEATURE_FLAG_LABEL)
-
-  if new_mr_title != helper.mr_title
-    changes[:title] = new_mr_title
-  else
-    message "You're adding or removing a feature flag, your MR title needs to include `[RUN ALL RSPEC] [RUN AS-IF-FOSS]` (we may have updated it automatically for you and started a new MR pipeline) to ensure everything is covered."
-  end
-
-  if changes.any?
-    gitlab.api.update_merge_request(
-      gitlab.mr_json['project_id'],
-      gitlab.mr_json['iid'],
-      **changes
-    )
-    gitlab.api.post("/projects/#{gitlab.mr_json['project_id']}/merge_requests/#{gitlab.mr_json['iid']}/pipelines")
-  end
-end

danger/specialization_labels/Dangerfile

@@ -9,7 +9,8 @@ SPECIALIZATIONS = {
   docs: 'documentation',
   qa: 'QA',
   engineering_productivity: 'Engineering Productivity',
-  ci_template: 'ci::templates'
+  ci_template: 'ci::templates',
+  feature_flag: 'feature flag'
 }.freeze
 
 labels_to_add = project_helper.changes_by_category.each_with_object([]) do |(category, _changes), memo|