[BUGFIX release] use import type in helpers/index.ts

typechecking in new apps fails atm

Author: NullVoxPopuli

blueprints/app/files/tests/helpers/index.ts

@@ -2,7 +2,7 @@ import {
   setupApplicationTest as upstreamSetupApplicationTest,
   setupRenderingTest as upstreamSetupRenderingTest,
   setupTest as upstreamSetupTest,
-  SetupTestOptions,
+  type SetupTestOptions,
 } from 'ember-qunit';
 
 // This file exists to provide wrappers around ember-qunit's