Remove sandbox extension of Frontboard XPC service.
<rdar://problem/118521486>
Pull request: https://github.com/WebKit/WebKit/pull/20622
Committed 270902@main (28a5e6a0092f): <https://commits.webkit.org/270902@main> Reviewed commits have been landed. Closing PR #20622 and removing active labels.
Re-opened since this is blocked by bug 265146
Pull request: https://github.com/WebKit/WebKit/pull/20749
Committed 270982@main (1f694659d812): <https://commits.webkit.org/270982@main> Reviewed commits have been landed. Closing PR #20749 and removing active labels.