Once we have added parsing support for the `transition-behavior` property, we need to account for it when starting transitions for properties that are not animatable.
<rdar://problem/119379014>
Pull request: https://github.com/WebKit/WebKit/pull/21535
Committed 271763@main (336b9f90b63d): <https://commits.webkit.org/271763@main> Reviewed commits have been landed. Closing PR #21535 and removing active labels.