Fix access to observers outside lock in ImageResponseObserverCoordinator (#52346)

Summary:
Pull Request resolved: #52346

This is bypassing the mutex, and potentially not thread-safe.

Changelog: [Internal]

Reviewed By: sammy-SC

Differential Revision: D77541041

fbshipit-source-id: f97415d066786864806836768dbce2d5e68487ef

Author: javache

packages/react-native/ReactCommon/react/renderer/imagemanager/ImageResponseObserverCoordinator.cpp

@@ -95,7 +95,7 @@ void ImageResponseObserverCoordinator::nativeImageResponseComplete(
   auto observers = observers_;
   mutex_.unlock();
 
-  for (auto observer : observers_) {
+  for (auto observer : observers) {
     observer->didReceiveImage(imageResponse);
   }
 }