Add sandbox telemetry for Mach lookup extensions in the WebContent process on iOS.
<rdar://problem/118114355>
Pull request: https://github.com/WebKit/WebKit/pull/20174
Committed 270638@main (eb8c417ba729): <https://commits.webkit.org/270638@main> Reviewed commits have been landed. Closing PR #20174 and removing active labels.
Re-opened since this is blocked by bug 264765