chore: add peerDependency on @ember/test-helpers

Author: BobrImperator

package.json

@@ -124,7 +124,7 @@
     "vite": "^7.1.9"
   },
   "peerDependencies": {
-    "ember-source": ">= 4.0.0"
+    "@ember/test-helpers": ">= 3.0.0"
   },
   "engines": {
     "node": ">= 20"