Stabilize RootTagContext

Summary:
Changelog:
[General][Removed] - Stabilize RootTagContext

Reviewed By: TheSavior

Differential Revision: D27954168

fbshipit-source-id: ff04375f00229b1a601cbd1182001885d8b687ec

Author: Nadiia D

index.js

@@ -479,9 +479,6 @@ module.exports = {
   ) => HostComponent<T> {
     return require('./Libraries/ReactNative/requireNativeComponent');
   },
-  get unstable_RootTagContext(): RootTagContext {
-    return require('./Libraries/ReactNative/RootTag').RootTagContext;
-  },
   get RootTagContext(): RootTagContext {
     return require('./Libraries/ReactNative/RootTag').RootTagContext;
   },