[WebGPU] RetainPtr used in a C-header outside of __cplusplus
<rdar://problem/127080816>
Pull request: https://github.com/WebKit/WebKit/pull/27775
Committed 278013@main (6c1e86905984): <https://commits.webkit.org/278013@main> Reviewed commits have been landed. Closing PR #27775 and removing active labels.