[ci] Deprecate yarn publish-prereleases

Added instructions on the new workflow. Let's keep this short around for
now as it may be used again due to muscle memory and emit a helpful
message instead.

ghstack-source-id: 3f840a3d4319309d31cefeae028f97d280b0c09a
Pull Request resolved: https://github.com/facebook/react/pull/30510