[WPT] Fix css-nesting test window size
<rdar://problem/105900204>
Pull request: https://github.com/WebKit/WebKit/pull/10664
Committed 260830@main (07fd62d3686f): <https://commits.webkit.org/260830@main> Reviewed commits have been landed. Closing PR #10664 and removing active labels.
Submitted web-platform-tests pull request: https://github.com/web-platform-tests/wpt/pull/38715