chore(deps): update dependency @ember/test-helpers to v4

Author: renovate[bot]

packages/test-app/package.json

@@ -27,7 +27,7 @@
     "@babel/eslint-parser": "7.25.9",
     "@ember/optional-features": "2.1.0",
     "@ember/string": "4.0.0",
-    "@ember/test-helpers": "3.3.1",
+    "@ember/test-helpers": "4.0.4",
     "@embroider/test-setup": "4.0.0",
     "@eslint/eslintrc": "3.1.0",
     "@eslint/js": "9.12.0",