Allow progamatically update focused TextInput state through ref.

[lucaswitch]

Given a <TextInput ref={inputRef} />

We could later do when needed. inputRef.current.setFocused(true);

Summary

Test plan

[drplauska]

is setFocused even a legit method? Can't seem to find it in types

[lucaswitch]

@drplauska is actually being discussed since the 4.12 update in #3146