Merge branch 'jnnkl-eventlistener-environment-index' into 'master'

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!53868

app/assets/javascripts/pages/projects/environments/index/index.js

 import initEnvironments from '~/environments/';
 
-document.addEventListener('DOMContentLoaded', initEnvironments);
+initEnvironments();