Fix header imports (#37625)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/37625

changelog: [internal]

- Add explicit <memory> import
- change include to import.

Reviewed By: FieryRobot

Differential Revision: D46284890

fbshipit-source-id: 8eb656c28f58295468b964e86f59b91ca562b570

packages/react-native/React/Fabric/RCTScheduler.mm

@@ -12,7 +12,7 @@
 #import <react/renderer/debug/SystraceSection.h>
 #import <react/renderer/scheduler/Scheduler.h>
 #import <react/renderer/scheduler/SchedulerDelegate.h>
-#include <react/utils/RunLoopObserver.h>
+#import <react/utils/RunLoopObserver.h>
 
 #import <React/RCTFollyConvert.h>