YARN-8295. [UI2] Improve Resource Usage tab error message when there are no data available. Contributed by Charan Hebri.

(cherry picked from commit 5b55f3538cb27baf8ac08568a5f752423e7b29a4)

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-ui/src/main/webapp/app/templates/yarn-app/charts.hbs

@@ -43,7 +43,7 @@
     </div>
   {{else}}
     <div class="panel panel-default">
-      <h4 class="text-center">No resource usage data is available for this application!</h4>
+      <h4 class="text-center">This application is not running. Hence no resource usage data is available.</h4>
     </div>
   {{/if}}
 </div>