Back out "Remove _shouldEmitEvent guardrails"

Summary:
Backout of this [commit]() as the previous one was making some E2E fail and need to investigate further.

## Changelog:
[Internal] - Add back `_shouldEmitEvent` guardrails

Reviewed By: mdvacca, arushikesarwani94

Differential Revision: D60467145

fbshipit-source-id: a703022aa74ca0ed0fed05b59da68918eb2001e1

packages/react-native/Libraries/NativeAnimation/RCTNativeAnimatedTurboModule.mm

@@ -27,6 +27,9 @@ typedef void (^AnimatedOperation)(RCTNativeAnimatedNodesManager *nodesManager);
   NSMutableArray<AnimatedOperation> *_preOperations;
 
   NSSet<NSString *> *_userDrivenAnimationEndedEvents;
+
+  // TODO: Remove this when https://github.com/facebook/react-native/pull/45457 lands
+  BOOL _shouldEmitEvent;
 }
 
 RCT_EXPORT_MODULE();
@@ -42,6 +45,7 @@ RCT_EXPORT_MODULE();
     _operations = [NSMutableArray new];
     _preOperations = [NSMutableArray new];
     _userDrivenAnimationEndedEvents = [NSSet setWithArray:@[ @"onScrollEnded" ]];
+    _shouldEmitEvent = NO;
   }
   return self;
 }
@@ -375,8 +379,27 @@ RCT_EXPORT_METHOD(queueAndExecuteBatchedOperations : (NSArray *)operationsAndArg
   [self sendEventWithName:@"onAnimatedValueUpdate" body:@{@"tag" : node.nodeTag, @"value" : @(value)}];
 }
 
+// TODO: Remove this when https://github.com/facebook/react-native/pull/45457 lands
+- (void)startObserving
+{
+  [super startObserving];
+  _shouldEmitEvent = YES;
+}
+
+- (void)stopObserving
+{
+  [super stopObserving];
+  _shouldEmitEvent = NO;
+}
+
+// ----
+
 - (void)userDrivenAnimationEnded:(NSArray<NSNumber *> *)nodes
 {
+  if (!_shouldEmitEvent) {
+    return;
+  }
+
   [self sendEventWithName:@"onUserDrivenAnimationEnded" body:@{@"tags" : nodes}];
 }