[motion-path] Check if we are mid layout when setting containing block rect for ray
<rdar://problem/113780201>
Pull request: https://github.com/WebKit/WebKit/pull/16633
Committed 267479@main (acfa97d238a3): <https://commits.webkit.org/267479@main> Reviewed commits have been landed. Closing PR #16633 and removing active labels.