Reduce visibility of FpsView

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 FpsView

bypass-github-export-checks

Reviewed By: arushikesarwani94

Differential Revision: D49803286

fbshipit-source-id: 2c4b7349de755d02a29cfdb97820b7af07709528

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

@@ -22,7 +22,7 @@
  *
  * <p>NB: Requires API 16 for use of FpsDebugFrameCallback.
  */
-public class FpsView extends FrameLayout {
+class FpsView extends FrameLayout {
 
   private static final int UPDATE_INTERVAL_MS = 500;