chore(deps): update ember testing to v5.4.3

Author: renovate[bot]

packages/test-app/package.json

@@ -28,7 +28,7 @@
     "@babel/eslint-parser": "7.28.6",
     "@ember/optional-features": "3.0.0",
     "@ember/string": "4.0.1",
-    "@ember/test-helpers": "5.4.2",
+    "@ember/test-helpers": "5.4.3",
     "@embroider/test-setup": "4.0.0",
     "@eslint/eslintrc": "3.3.5",
     "@eslint/js": "9.39.4",