Allow ImageBitmap to be created from ImageBitmap::Source without needing a Promise
<rdar://problem/108270485>
Pull request: https://github.com/WebKit/WebKit/pull/12920
Committed 263143@main (cc807585594a): <https://commits.webkit.org/263143@main> Reviewed commits have been landed. Closing PR #12920 and removing active labels.