Immediately destroy the session for banned users

Immediately destroy the session for banned users

The forced logout for banned users was introduced in
ab84d9cab2f864c23f0b18dbeb67e7ea79b1fe9f and only destroyed the session during
shutdown.

At the point where this check runs the request effectively is fully booted up
and in any case the NamedUserException would abort any further booting, thus it
is safe to simply destroy the session immediately to keep all the necessary
logic in a single location.