[iPad] Vimeo video goes black navigating from PiP back to full screen
<rdar://problem/107592139>
Pull request: https://github.com/WebKit/WebKit/pull/12499
Committed 262703@main (dc8a2c99f4be): <https://commits.webkit.org/262703@main> Reviewed commits have been landed. Closing PR #12499 and removing active labels.