Summary:
part of #24875. Because some of the methods are rewriteable, I dropped the `+` from the signature, this doesn't feel right to me, but I am not sure if the codegen requires that. If it does, it will probably be better to extend the spec and allow those specific methods to be overriden in a UIManager.js interface. Thoughts on that fkgozali or RSNara?
## Changelog
[General] [Added] - Add TM spec for UIManager
Pull Request resolved: https://github.com/facebook/react-native/pull/24902
Reviewed By: hramos
Differential Revision: D15551356
Pulled By: fkgozali
fbshipit-source-id: 076c4ce635aa7ea41e21cbd67c47ecd562fc320d