refactor: 💡 replace ember notify with flash in notify decorator (#1272)

* refactor: 💡 replace ember notify with flash in notify decorator

* refactor: 💡 remove embery-notify and replace last instance

ui/desktop/tests/test-helper.js

@@ -4,6 +4,7 @@ import * as QUnit from 'qunit';
 import { setApplication } from '@ember/test-helpers';
 import { setup } from 'qunit-dom';
 import { start } from 'ember-qunit';
+import './helpers/flash-message';
 
 setApplication(Application.create(config.APP));