3rd-party cookies are not disabled anymore in Tor Browser 11

I got pinged by a cypherpunk today who pretty much rambled about the state of Tor Browser 11. But between all of that there seems to be a valid bug report which we should follow-up with.

Tor Browser 11 does not disable third-party cookies anymore compared to Tor Browser 10.5, at least according to https://www.whatismybrowser.com/detect/are-third-party-cookies-enabled.

The same cypherpunk felt the urge to paste a link to https://bugzilla.mozilla.org/show_bug.cgi?id=1698843 in an unrelated ticket pointing out on IRC that the changes mentioned there are supposed to be related to this bug.