Fixed transient user merges immediately spec

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/9206

spec/features/merge_request/user_merges_immediately_spec.rb

@@ -25,6 +25,8 @@ describe 'Merge requests > User merges immediately', :js do
     end
 
     it 'enables merge immediately' do
+      wait_for_requests
+
       page.within '.mr-widget-body' do
         find('.dropdown-toggle').click