[WebGPU] WebGPU is not working correctly in an offscreen canvas
<rdar://problem/119698186>
Pull request: https://github.com/WebKit/WebKit/pull/21842
Committed 272515@main (1598a12d851c): <https://commits.webkit.org/272515@main> Reviewed commits have been landed. Closing PR #21842 and removing active labels.