Reduce visibility of RefreshEvent

Summary:
In an attempt to reduce footprint of React Native Android public APIs we are reducing visibility of classes and interfaces that are not meant to be used publicly OR are public but have no usages.
As part of our analysis, which involved looking for usages inside the Meta codebase and code search in OSS, we've detected that this class/interface is public but it's not used from other packages.

If you are using this class or interface please comment in this PR and we will restate the public access.

bypass-github-export-checks

changelog: [Android][Changed] Reducing visibility of RefreshEvent

Reviewed By: arushikesarwani94

Differential Revision: D49803298

fbshipit-source-id: f8edfd256b3afc82bb02789b34748abb3132cce1

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/views/swiperefresh/RefreshEvent.java

@@ -13,7 +13,7 @@
 import com.facebook.react.uimanager.common.ViewUtil;
 import com.facebook.react.uimanager.events.Event;
 
-public class RefreshEvent extends Event<RefreshEvent> {
+class RefreshEvent extends Event<RefreshEvent> {
 
   @Deprecated
   protected RefreshEvent(int viewTag) {