fix(docker-vm): add error handling for virt-customize finalization

The hostname/machine-id virt-customize calls had no error handling,
unlike the SSH config calls just below them which already use || true.
When virt-customize fails (e.g. on certain Debian 13 images), the
script aborted instead of continuing gracefully.
These steps are not critical — Cloud-Init can set the hostname later.

Closes #12073

vm/docker-vm.sh

@@ -525,9 +525,9 @@ fi
 
 msg_info "Finalizing image (hostname, SSH config)"
 # Set hostname and prepare for unique machine-id
-virt-customize -q -a "$WORK_FILE" --hostname "${HN}" >/dev/null 2>&1
-virt-customize -q -a "$WORK_FILE" --run-command "truncate -s 0 /etc/machine-id" >/dev/null 2>&1
-virt-customize -q -a "$WORK_FILE" --run-command "rm -f /var/lib/dbus/machine-id" >/dev/null 2>&1
+virt-customize -q -a "$WORK_FILE" --hostname "${HN}" >/dev/null 2>&1 || true
+virt-customize -q -a "$WORK_FILE" --run-command "truncate -s 0 /etc/machine-id" >/dev/null 2>&1 || true
+virt-customize -q -a "$WORK_FILE" --run-command "rm -f /var/lib/dbus/machine-id" >/dev/null 2>&1 || true
 
 # Configure SSH for Cloud-Init
 if [ "$USE_CLOUD_INIT" = "yes" ]; then