Merge branch 'jnnkl-eventlistener-release-edit' into 'master'

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!53852

app/assets/javascripts/pages/projects/releases/edit/index.js

 import ZenMode from '~/zen_mode';
 import initEditRelease from '~/releases/mount_edit';
 
-document.addEventListener('DOMContentLoaded', () => {
-  new ZenMode(); // eslint-disable-line no-new
-  initEditRelease();
-});
+new ZenMode(); // eslint-disable-line no-new
+initEditRelease();