fix: replace debian:bullseye with trixie image

The realtime-hack with the image debian:bullseye failed with the message Release file for http://deb.debian.org/debian-security/dists/bullseye-security/InRelease is expired so we bump the image to the latest stable Debian distribution.

Also added a check for the realtime-hack to the run-tests.sh script because I wasted too much time debugging the databases.