WinCairo WK1 was removed. So AuthenticationClient-related code in AuthenticationChallenge are no longer needed..
Pull request: https://github.com/WebKit/WebKit/pull/14908
Committed 265107@main (0c9a3b2b845d): <https://commits.webkit.org/265107@main> Reviewed commits have been landed. Closing PR #14908 and removing active labels.
<rdar://problem/110692575>