Remove use_upsert_query_for_mr_metrics FF

app/models/merge_request.rb

@@ -1884,30 +1884,7 @@ class MergeRequest < ApplicationRecord
 
   override :ensure_metrics
   def ensure_metrics
-    if Feature.enabled?(:use_upsert_query_for_mr_metrics, default_enabled: :yaml)
-      MergeRequest::Metrics.record!(self)
-    else
-      # Backward compatibility: some merge request metrics records will not have target_project_id filled in.
-      # In that case the first `safe_find_or_create_by` will return false.
-      # The second finder call will be eliminated in https://gitlab.com/gitlab-org/gitlab/-/issues/233507
-      metrics_record = MergeRequest::Metrics.safe_find_or_create_by(merge_request_id: id, target_project_id: target_project_id) || MergeRequest::Metrics.safe_find_or_create_by(merge_request_id: id)
-
-      metrics_record.tap do |metrics_record|
-        # Make sure we refresh the loaded association object with the newly created/loaded item.
-        # This is needed in order to have the exact functionality than before.
-        #
-        # Example:
-        #
-        # merge_request.metrics.destroy
-        # merge_request.ensure_metrics
-        # merge_request.metrics # should return the metrics record and not nil
-        # merge_request.metrics.merge_request # should return the same MR record
-
-        metrics_record.target_project_id = target_project_id
-        metrics_record.association(:merge_request).target = self
-        association(:metrics).target = metrics_record
-      end
-    end
+    MergeRequest::Metrics.record!(self)
   end
 
   def allows_reviewers?

config/feature_flags/development/use_upsert_query_for_mr_metrics.yml

----
-name: use_upsert_query_for_mr_metrics
-introduced_by_url: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/69240
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/339677
-milestone: '14.3'
-type: development
-group: group::optimize
-default_enabled: true