Fix handling of grid-template-columns / grid-template-rows in CSS Typed OM.
Pull request: https://github.com/WebKit/WebKit/pull/7863
Committed 258102@main (a5f4bb317a21): <https://commits.webkit.org/258102@main> Reviewed commits have been landed. Closing PR #7863 and removing active labels.
<rdar://problem/103534407>