Summary:
Restoring the copyright header on some files, in order to fix an internal lint failure that is raised whenever these files are edited on open source.
Closes https://github.com/facebook/react-native/pull/17912
Differential Revision: D6938189
Pulled By: hramos
fbshipit-source-id: 6447d8ad6d7ecce0ef5f1821f63e44957bbf6d15