WebCodecsVideoDecoderConfig description should be undefined instead of null if there is no description to provide
<rdar://problem/101288923>
Pull request: https://github.com/WebKit/WebKit/pull/5490
Committed 255726@main (146ca511cb11): <https://commits.webkit.org/255726@main> Reviewed commits have been landed. Closing PR #5490 and removing active labels.
Re-opened since this is blocked by bug 246740
Pull request: https://github.com/WebKit/WebKit/pull/5578
Committed 255780@main (35adb599351f): <https://commits.webkit.org/255780@main> Reviewed commits have been landed. Closing PR #5578 and removing active labels.