YARN-11312: [UI2] Refresh buttons don't work after EmberJS upgrade (#5649)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/app/components/breadcrumb-bar.js

@@ -25,7 +25,7 @@ export default Ember.Component.extend({
 
   actions:{
     refresh: function () {
-      this.get("targetObject").send("refresh");
+      this.get("_targetObject").send("refresh");
     }
   }