IGNITE-4394 Web Console: Fixed memory leak in Messages.service.

Author: AlexDel

modules/web-console/frontend/app/services/Messages.service.js

@@ -44,8 +44,11 @@ export default ['IgniteMessages', ['$alert', ($alert) => {
     };
 
     const hideAlert = () => {
-        if (msgModal)
+        if (msgModal) {
             msgModal.hide();
+            msgModal.destroy();
+            msgModal = null;
+        }
     };
 
     const _showMessage = (message, err, type, duration) => {