Summary:
This PR makes the android dev menu consistent with iOS where toggling the inspector will update the button label accordingly.
Closes https://github.com/facebook/react-native/pull/4628
Reviewed By: svcscm
Differential Revision: D2740549
Pulled By: mkonicek
fb-gh-sync-id: 02458d09b84e1592dcf245290ee2bbfb2863060d