MT#55898 User tests: recent openssh versions use _ssh group name

The openssh-server Debian package no longer uses the "ssh" group,
but renamed it to "_ssh" (see git rev 18da782e in
https://salsa.debian.org/ssh-team/openssh.git + Debian's #990456), which
was shipped starting with v1:8.4p1-6.

Debian/bookworm currently ships openssh-server v1:9.0p1-1+b2,
so adjust tests accordingly.

Change-Id: I4f75e94ac32ce9d06a4bc9991fa62b73086e4f45

ngcp-system-tests

@@ -81,6 +81,9 @@ case "${NGCP_TESTS_MODE}" in
       bullseye*)
         DEBIAN_RELEASE=11
         ;;
+      bookworm*)
+        DEBIAN_RELEASE=12
+        ;;
     esac
     export DEBIAN_RELEASE
 

templates/200_user-debian.yaml.tt2

@@ -22,8 +22,13 @@ group:
     exists: true
     gid: 0
 
+{{if eq .Env.DEBIAN_RELEASE "11"}}
   ssh:
     exists: true
+{{else}}
+  _ssh:
+    exists: true
+{{end}}
 
   ssl-cert:
     exists: true