Reject getDisplayMedia prompt if user doesn't choose a window or screen, or if the system picker fails internally.
rdar://98194903
Pull request: https://github.com/WebKit/WebKit/pull/3110
Committed 253260@main (bbf09215e01b): <https://commits.webkit.org/253260@main> Reviewed commits have been landed. Closing PR #3110 and removing active labels.