Suricata: detect DNS events on port 853, too

As DNS over TLS popularity is increasing, port 853 becomes
more interesting for an attacker as a bypass method. Enabling
this port for DNS monitoring makes sense in order to avoid
unusual activity (non-DNS traffic) as well as "normal" DNS
attacks.

Partially fixes #11808

Signed-off-by: Peter Müller <peter.mueller@ipfire.org>
Cc: Stefan Schantl <stefan.schantl@ipfire.org>
Signed-off-by: Stefan Schantl <stefan.schantl@ipfire.org>