Add <hash-token> consumption for CSSTokenizer (#44613)

Summary:
Pull Request resolved: https://github.com/facebook/react-native/pull/44613

We are building a native CSS parser for Fabric, to allow broader support for CSS. One area not yet implemented are features required for color.

<hash-token> is a pre-requisite.

Changelog: [Internal]

Reviewed By: NickGerleman

Differential Revision: D57180293

fbshipit-source-id: 0932c44d881f205aed55bcdf4fa23ad04b336c11