refactor: 💡 upgrade ui/desktop to Ember 3.24

ui/desktop/tests/test-helper.js

@@ -1,8 +1,12 @@
-import Application from '../app';
-import config from '../config/environment';
+import Application from 'desktop/app';
+import config from 'desktop/config/environment';
+import * as QUnit from 'qunit';
 import { setApplication } from '@ember/test-helpers';
+import { setup } from 'qunit-dom';
 import { start } from 'ember-qunit';
 
 setApplication(Application.create(config.APP));
 
+setup(QUnit.assert);
+
 start();