fix fantom test

Author: hannojg

packages/react-native/ReactCxxPlatform/react/renderer/scheduler/SchedulerDelegateImpl.cpp

@@ -63,4 +63,10 @@ void SchedulerDelegateImpl::schedulerDidUpdateShadowTree(
   mountingManager_->onUpdateShadowTree(tagToProps);
 }
 
+void SchedulerDelegateImpl::schedulerMeasureAsyncOnUI(
+    const ShadowView& shadowView,
+    const std::function<void(folly::dynamic)>& callback) {
+  // No-op implementation, can be overridden by subclasses if needed
+}
+
 } // namespace facebook::react

packages/react-native/ReactCxxPlatform/react/renderer/scheduler/SchedulerDelegateImpl.h

@@ -59,6 +59,10 @@ class SchedulerDelegateImpl : public SchedulerDelegate {
   void schedulerDidUpdateShadowTree(
       const std::unordered_map<Tag, folly::dynamic>& tagToProps) override;
 
+  void schedulerMeasureAsyncOnUI(
+      const ShadowView& shadowView,
+      const std::function<void(folly::dynamic)>& callback) override;
+
   std::shared_ptr<IMountingManager> mountingManager_;
 };