refactor: Update 'core' app references to 'admin'

ui/admin/tests/test-helper.js

@@ -1,5 +1,5 @@
-import Application from 'core/app';
-import config from 'core/config/environment';
+import Application from '../app';
+import config from '../config/environment';
 import { setApplication } from '@ember/test-helpers';
 //import { start } from 'ember-qunit';
 import start from 'ember-exam/test-support/start';