Tweak test helpers

Author: RobbieTheWagner

package.json

@@ -108,7 +108,8 @@
     "@ember-data/store": "^5.8.0",
     "@ember/optional-features": "^2.2.0",
     "@ember/string": "^3.1.1",
-    "@ember/test-helpers": "^4.0.5",
+    "@ember/test-helpers": "^3.3.1",
+    "@ember/test-waiters": "^3.1.0",
     "@embroider/test-setup": "^3.0.3",
     "@fullhuman/postcss-purgecss": "^4.1.3",
     "@release-it-plugins/lerna-changelog": "^7.0.0",