Conditionally block access to service in sandbox on iOS based on a new experimental sandbox setting.
<rdar://problem/101295943>
Pull request: https://github.com/WebKit/WebKit/pull/5495
Committed 255830@main (d5160fa6b1b8): <https://commits.webkit.org/255830@main> Reviewed commits have been landed. Closing PR #5495 and removing active labels.