Remove allow_n_plus_1_calls from MergeRequests::CreateService

Fixes #37439
Fixes gitaly#1000

app/services/merge_requests/create_service.rb

@@ -9,10 +9,7 @@ module MergeRequests
       merge_request.source_branch = params[:source_branch]
       merge_request.merge_params['force_remove_source_branch'] = params.delete(:force_remove_source_branch)
-      # n+1: https://gitlab.com/gitlab-org/gitlab-ce/issues/37439
-      Gitlab::GitalyClient.allow_n_plus_1_calls do
-        create(merge_request)
-      end
+      create(merge_request)
     end
     def before_create(merge_request)