Entering/Leaving YouTube fullscreen causes the video to not scale fully to screen edges
<rdar://problem/102970285>
Pull request: https://github.com/WebKit/WebKit/pull/12134
Committed 262311@main (f06787f3c33a): <https://commits.webkit.org/262311@main> Reviewed commits have been landed. Closing PR #12134 and removing active labels.