Reduce visibility of ViewHierarchyUtil

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.

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

bypass-github-export-checks

Reviewed By: arushikesarwani94

Differential Revision: D49803291

fbshipit-source-id: 929608f71ce3c5af842616add21ac9077239e109

packages/react-native/ReactAndroid/src/main/java/com/facebook/react/devsupport/ViewHierarchyUtil.java

@@ -14,7 +14,7 @@
 import java.util.Queue;
 
 /** Helper for computing information about the view hierarchy */
-public class ViewHierarchyUtil {
+class ViewHierarchyUtil {
 
   /** Returns the view instance and depth of the deepest leaf view from the given root view. */
   public static Pair<View, Integer> getDeepestLeaf(View root) {