Merge branch 'jnnkl-eventlistener-serverless' into 'master'

Remove obsolete DOMContentLoadedEventListener

See merge request gitlab-org/gitlab!53972

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

 import ServerlessBundle from '~/serverless/serverless_bundle';
 import initServerlessSurveyBanner from '~/serverless/survey_banner';
 
-document.addEventListener('DOMContentLoaded', () => {
-  initServerlessSurveyBanner();
-  new ServerlessBundle(); // eslint-disable-line no-new
-});
+initServerlessSurveyBanner();
+new ServerlessBundle(); // eslint-disable-line no-new