Merge branch '47830-merge-request-diff-loading-icon-not-visible' into 'master'

Resolve "Merge request diff loading icon not visible"

Closes #47830 and #47849

See merge request gitlab-org/gitlab-ce!19758

app/assets/javascripts/merge_request_tabs.js

@@ -362,7 +362,7 @@ export default class MergeRequestTabs {
   //
   // status - Boolean, true to show, false to hide
   toggleLoading(status) {
-    $('.mr-loading-status .loading').toggleClass('hidden', !status);
+    $('.mr-loading-status .loading').toggleClass('hide', !status);
   }
 
   diffViewType() {