Dispatch native handled events to JS

Summary:
When native events where handled they were not sent to JS as an optimization but this caused some issues. One of the major one is touches are not handled properly inside a ScrollView with an Animated.event because it doesn't receive scroll events so it can't cancel the touch if the user scrolled.
Closes https://github.com/facebook/react-native/pull/10981

Differential Revision: D4226403

Pulled By: astreet

fbshipit-source-id: 41278d3ed4b684af142d9e273b11b974eb679879

Libraries/NativeAnimation/RCTNativeAnimatedModule.m

@@ -322,11 +322,11 @@ RCT_EXPORT_METHOD(removeAnimatedEventFromView:(nonnull NSNumber *)viewTag
                      body:@{@"tag": node.nodeTag, @"value": @(value)}];
 }
 
-- (BOOL)eventDispatcherWillDispatchEvent:(id<RCTEvent>)event
+- (void)eventDispatcherWillDispatchEvent:(id<RCTEvent>)event
 {
   // Native animated events only work for events dispatched from the main queue.
   if (!RCTIsMainQueue() || _eventAnimationDrivers.count == 0) {
-    return NO;
+    return;
   }
 
   NSString *key = [NSString stringWithFormat:@"%@%@", event.viewTag, event.eventName];
@@ -336,11 +336,7 @@ RCT_EXPORT_METHOD(removeAnimatedEventFromView:(nonnull NSNumber *)viewTag
     [driver updateWithEvent:event];
     [self updateViewsProps];
     [driver.valueNode cleanupAnimationUpdate];
-
-    return YES;
   }
-
-  return NO;
 }
 
 - (void)updateViewsProps