Expose JSResponderHandler API in Fabric UIManager

Summary:
This diff adds the new API required to implment JSResponderHandler in FabricUIManager
The new API differs from the old API, but since setJSResponder is called ONLY from JS it's not necessary to have this method as part of UIManager interface.

Reviewed By: JoshuaGross

Differential Revision: D16543440

fbshipit-source-id: ca4bd4c1e4df706cda0eb16798e01f3350558d06

ReactAndroid/src/main/java/com/facebook/react/uimanager/UIManagerModule.java

@@ -650,13 +650,11 @@ public class UIManagerModule extends ReactContextBaseJavaModule
     mUIImplementation.viewIsDescendantOf(reactTag, ancestorReactTag, callback);
   }
 
-  @Override
   @ReactMethod
   public void setJSResponder(int reactTag, boolean blockNativeResponder) {
     mUIImplementation.setJSResponder(reactTag, blockNativeResponder);
   }
 
-  @Override
   @ReactMethod
   public void clearJSResponder() {
     mUIImplementation.clearJSResponder();