Removed event-target-shim dependency

Author: monadoid

packages/agents-core/package.json

@@ -81,7 +81,6 @@
     "@openai/zod": "npm:zod@^3.25.40",
     "@ungap/structured-clone": "^1.3.0",
     "debug": "^4.4.0",
-    "event-target-shim": "^6.0.2",
     "events": "^3.3.0",
     "openai": "^6",
     "react-native-uuid": "^2.0.3"