InputDevice capabilities are not exposed until after the user has given consent to capture, so don't bother asking for them unless they will be revealed.
rdar://113271473
Pull request: https://github.com/WebKit/WebKit/pull/16380
Committed 266581@main (a41543cba4bf): <https://commits.webkit.org/266581@main> Reviewed commits have been landed. Closing PR #16380 and removing active labels.