[RN] Move new event dispatching pipeline to RN (#36266)

## Summary

We found a bug in the logic in
#36253 and we realized it's very
inconvenient to iterate on the implementation when it's in this
repository, as we're forced to then synchronize it to RN to test
changes.

This moves the entire implementation to RN for simplicity and also to
simplify some clean ups in the future (like removing `top` prefixes from
native event types).

## How did you test this change?

The changes are gated. Will test e2e in RN.

Author: rubennorte

packages/react-native-renderer/src/ReactFabricEventEmitter.js

@@ -30,21 +30,13 @@ import {runEventsInBatch} from './legacy-events/EventBatching';
 
 import {
   RawEventEmitter,
-  ReactNativeViewConfigRegistry,
-  dispatchTrustedEvent,
-  setEventInitTimeStamp,
+  dispatchNativeEvent,
 } from 'react-native/Libraries/ReactPrivate/ReactNativePrivateInterface';
 import {getPublicInstance} from './ReactFiberConfigFabric';
-import LegacySyntheticEvent from './LegacySyntheticEvent';
-import {topLevelTypeToEventName} from './ReactNativeEventTypeMapping';
-import {processResponderEvent} from './ReactNativeResponder';
 import {enableNativeEventTargetEventDispatching} from './ReactNativeFeatureFlags';
 
 export {getListener, registrationNameModules as registrationNames};
 
-const {customBubblingEventTypes, customDirectEventTypes} =
-  ReactNativeViewConfigRegistry;
-
 /**
  * Allows registered plugins an opportunity to extract events from top-level
  * native browser events.
@@ -143,38 +135,8 @@ export function dispatchEvent(
     RawEventEmitter.emit('*', event);
 
     if (enableNativeEventTargetEventDispatching()) {
-      // Process responder events before normal event dispatch.
-      // This handles touch negotiation (onStartShouldSetResponder, etc.)
-      processResponderEvent(topLevelType, targetFiber, nativeEvent);
-
-      // New EventTarget-based dispatch path
       if (eventTarget != null) {
-        const bubbleDispatchConfig = customBubblingEventTypes[topLevelType];
-        const directDispatchConfig = customDirectEventTypes[topLevelType];
-        const bubbles = bubbleDispatchConfig != null;
-
-        // Skip events that are not registered in the view config
-        if (bubbles || directDispatchConfig != null) {
-          const eventName = topLevelTypeToEventName(topLevelType);
-          const options = {
-            bubbles,
-            cancelable: true,
-          };
-          // Preserve the native event timestamp for backwards compatibility.
-          // The legacy SyntheticEvent system used nativeEvent.timeStamp || nativeEvent.timestamp.
-          const nativeTimestamp =
-            nativeEvent.timeStamp ?? nativeEvent.timestamp;
-          if (typeof nativeTimestamp === 'number') {
-            setEventInitTimeStamp(options, nativeTimestamp);
-          }
-          const syntheticEvent = new LegacySyntheticEvent(
-            eventName,
-            options,
-            nativeEvent,
-          );
-          // $FlowFixMe[incompatible-call]
-          dispatchTrustedEvent(eventTarget, syntheticEvent);
-        }
+        dispatchNativeEvent(eventTarget, topLevelType, nativeEvent);
       }
     } else {
       // Heritage plugin event system