Mark IViewGroupManager interface as @nullsafe (facebook#43157)

Summary:
Pull Request resolved: facebook#43157

IViewGroupManager is NullSafe, let's mark them as NullSafe(Local) to ensure lint detect errors in the future

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changelog: [internal] internal

Reviewed By: rshest

Differential Revision: D54034058

fbshipit-source-id: ad317c73d45fdd801aeee65d5308400e2e1c8552

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/uimanager/IViewGroupManager.java

@@ -8,9 +8,11 @@
 package com.facebook.react.uimanager;
 
 import android.view.View;
+import com.facebook.infer.annotation.Nullsafe;
 import com.facebook.react.bridge.UiThreadUtil;
 
 /** Interface providing children management API for view managers of classes extending ViewGroup. */
+@Nullsafe(Nullsafe.Mode.LOCAL)
 public interface IViewGroupManager<T extends View> extends IViewManagerWithChildren {
 
   /** Adds a child view into the parent at the index specified as a parameter */