Disable builtInNotification endpoints when builtInNotificationsEnabled is set to false
<rdar://problem/112769420>
Pull request: https://github.com/WebKit/WebKit/pull/16036
Committed 266259@main (90608fd2ccb6): <https://commits.webkit.org/266259@main> Reviewed commits have been landed. Closing PR #16036 and removing active labels.
Re-opened since this is blocked by bug 259475
Pull request: https://github.com/WebKit/WebKit/pull/16063
Committed 266312@main (e68eac0ee93a): <https://commits.webkit.org/266312@main> Reviewed commits have been landed. Closing PR #16063 and removing active labels.