AMBARI-25568: The 'NodeManager RAM Utilized' metric in the heatmap of YARN does not show the unit (#3551)

ambari-server/src/main/resources/stacks/BIGTOP/3.2.0/services/YARN/YARN_widgets.json

@@ -577,7 +577,7 @@
             }
           ],
           "properties": {
-            "display_unit": "",
+            "display_unit": "GB",
             "max_limit": "100"
           }
         },