Use SyncCodeOwnerApprovalRulesWorker when creating merge request

ee/app/services/ee/merge_requests/create_service.rb

@@ -9,7 +9,7 @@ module EE
       def after_create(issuable)
         super
 
-        ::MergeRequests::SyncCodeOwnerApprovalRules.new(issuable).execute
+        ::MergeRequests::SyncCodeOwnerApprovalRulesWorker.perform_async(issuable.id)
         ::MergeRequests::SyncReportApproverApprovalRules.new(issuable).execute
 
         ::MergeRequests::UpdateBlocksService

ee/changelogs/unreleased/20770-move-approval-rules-to-sidekiq1.yml

+---
+title: Sync code owner approval rules asynchronously after creating merge request
+merge_request: 59395
+author:
+type: performance

ee/spec/services/ee/merge_requests/create_service_spec.rb

@@ -28,14 +28,11 @@ RSpec.describe MergeRequests::CreateService do
       project.add_maintainer(user)
     end
 
-    it 'refreshes code owners for the merge request' do
-      fake_refresh_service = instance_double(::MergeRequests::SyncCodeOwnerApprovalRules)
-
-      expect(::MergeRequests::SyncCodeOwnerApprovalRules)
-        .to receive(:new).with(kind_of(MergeRequest)).and_return(fake_refresh_service)
-      expect(fake_refresh_service).to receive(:execute)
-
-      service.execute
+    it 'schedules refresh of code owners for the merge request' do
+      Sidekiq::Testing.fake! do
+        expect { service.execute }.to change(::MergeRequests::SyncCodeOwnerApprovalRulesWorker.jobs, :size).by(1)
+        ::MergeRequests::SyncCodeOwnerApprovalRulesWorker.clear
+      end
     end
 
     context 'report approvers' do