[RN] Expose event as a global variable during dispatch (#35913)

## Summary

This PR updates the event dispatching logic in React Native to expose
the dispatched event in the global scope as done on Web
(https://dom.spec.whatwg.org/#concept-event-listener-inner-invoke) and
in the new implementation of `EventTarget` in React Native
(https://github.com/facebook/react-native/blob/d1b2ddc9cb4f7b4cb795fed197347173ed5c4bfb/packages/react-native/src/private/webapis/dom/events/EventTarget.js#L372).

## How did you test this change?

Added unit tests