Clean up code to reuse helper function

Editor assessment

chore(radio-group) says the code is cleaned up to reuse a helper function, with the pull request in the header and a co-author credited. The scope and chore type fit, and the subject is imperative and unterminated. The change is a small internal cleanup, so the absence of a body is acceptable, though clean up could be more specific. Understandable and correctly classified, it is publishable.