fix(iOS): Replace uses of `CGColorRef` with UIColor to avoid manual memory management v2 (#47019)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/47019

NOTE: This code is largely the same as https://github.com/facebook/react-native/pull/46847, I am merely fixing some internal issues

The original diff (D63989547) was backed out because it was causing some crashes related to some internal code that had to be changed. That code did not necessarily need to be changed - we could have just left the `RCTCreateCGColorRefFromSharedColor` function and not touched the internal code - which is what I am going to do here

Changelog: [Internal]

Reviewed By: NickGerleman

Differential Revision: D64201626

fbshipit-source-id: a8ead7a542514aee0749973e284cb7727d393c03