fix(react-native): add a default value for the withCredentials option
fix(react-native): add a default value for the withCredentials option

The undefined value breaks React Native on Android with a rather cryptic error message:

```
Attempt to invoke virtual method 'boolean java.lang.Boolean.booleanValue() on a null object reference
```

This bug was introduced by [1].

[1]: https://github.com/socketio/engine.io-client/commit/5f47a50ee5dc47962f3823f4e8dde0b4b407eccd

Related: https://github.com/socketio/socket.io-client/issues/1403

Automattic/engine.io-client,socketio/engine.io-client,socketio/engine.io-client,socketio/engine.io-client