fix fantom test

Author: hannojg

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

@@ -87,4 +87,10 @@ void SchedulerDelegateImpl::schedulerDidSetViewSnapshot(
 
 void SchedulerDelegateImpl::schedulerDidClearPendingSnapshots() {}
 
+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

@@ -57,6 +57,10 @@ class SchedulerDelegateImpl : public SchedulerDelegate {
 
   void schedulerDidClearPendingSnapshots() override;
 
+  void schedulerMeasureAsyncOnUI(
+      const ShadowView& shadowView,
+      const std::function<void(folly::dynamic)>& callback) override;
+
   std::shared_ptr<IMountingManager> mountingManager_;
   std::shared_ptr<UIManager> uiManager_;
 };