[WebGPU] Revert 263054@main "Make RemoteGPU owned by RemoteRenderingBackend rather than GPUConnectionToWebProcess"
<rdar://problem/109432358>
Pull request: https://github.com/WebKit/WebKit/pull/13945
Committed 264187@main (cd1e2eb65f29): <https://commits.webkit.org/264187@main> Reviewed commits have been landed. Closing PR #13945 and removing active labels.