* Move view config registry to shims
This ensures that both Fabric and RN renderers share the same view config
registry since it is stateful.
I had to duplicate in the mocks for testing.
* Move createReactNativeComponentClass to shims and delete internal usage
Since createReactNativeComponentClass is just an alias for the register
there's no need to bundle it. This file should probably just move back
to RN too.
This is not safe in general and therefore shouldn't be exposed to anything
other than React Native internals.
It will also need a different version in Fabric that will not have the
reactTag exposed.