Mark UIManagerModuleConstantsHelper.normalizeEventTypes as Nullable

Summary:
Mark UIManagerModuleConstantsHelper.normalizeEventTypes as Nullable

changelog: [internal] internal

Reviewed By: arushikesarwani94

Differential Revision: D54327799

fbshipit-source-id: 66dd42c8ed220e76c62e3d215c59d6547c374265

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

@@ -180,7 +180,7 @@ private static void validateDirectEventNames(
   }
 
   @VisibleForTesting
-  /* package */ static void normalizeEventTypes(Map events) {
+  /* package */ static void normalizeEventTypes(@Nullable Map events) {
     if (events == null) {
       return;
     }