Create binding for unmountComponentAtNode in bridgeless mode

Summary: Right now we register ReactFabric as a callable module with the bridge so that we can call `ReactFabric.unmountComponentAtNode` in `ReactInstanceManager.detachViewFromInstance`. In bridgeless mode we don't have callable modules, so I'm just setting a global variable that can be called from C++ instead. Using this in a new `unmount` method in FabricUIManager.

Reviewed By: shergin, mdvacca

Differential Revision: D16273720

fbshipit-source-id: 95edb16da6566113a58babda3ebdf0fc4e39f8b0

Author: Emily Janzer

Libraries/Renderer/shims/ReactFabric.js

@@ -23,6 +23,12 @@ if (__DEV__) {
   ReactFabric = require('../implementations/ReactFabric-prod');
 }
 
-BatchedBridge.registerCallableModule('ReactFabric', ReactFabric);
+if (global.RN$Bridgeless) {
+  // TODO T47525605 Clean this up once stopSurface has been added
+  global.RN$stopSurface =
+    ReactFabric.stopSurface ?? ReactFabric.unmountComponentAtNode;
+} else {
+  BatchedBridge.registerCallableModule('ReactFabric', ReactFabric);
+}
 
 module.exports = (ReactFabric: ReactNativeType);

ReactAndroid/src/main/java/com/facebook/react/fabric/FabricUIManager.java

@@ -182,6 +182,10 @@ public void onRequestEventBeat() {
     mEventDispatcher.dispatchAllEvents();
   }
 
+  public void stopSurface(int surfaceID) {
+    mBinding.stopSurface(surfaceID);
+  }
+
   @Override
   public void initialize() {
     mEventDispatcher.registerEventEmitter(FABRIC, new FabricEventEmitter(this));

ReactCommon/fabric/uimanager/UIManagerBinding.cpp

@@ -69,10 +69,17 @@ void UIManagerBinding::startSurface(
 
 void UIManagerBinding::stopSurface(jsi::Runtime &runtime, SurfaceId surfaceId)
     const {
-  auto module = getModule(runtime, "ReactFabric");
-  auto method = module.getPropertyAsFunction(runtime, "unmountComponentAtNode");
+  if (runtime.global().hasProperty(runtime, "RN$stopSurface")) {
+    auto method =
+        runtime.global().getPropertyAsFunction(runtime, "RN$stopSurface");
+    method.call(runtime, {jsi::Value{surfaceId}});
+  } else {
+    auto module = getModule(runtime, "ReactFabric");
+    auto method =
+        module.getPropertyAsFunction(runtime, "unmountComponentAtNode");
 
-  method.callWithThis(runtime, module, {jsi::Value{surfaceId}});
+    method.callWithThis(runtime, module, {jsi::Value{surfaceId}});
+  }
 }
 
 void UIManagerBinding::dispatchEvent(