Only set up oem-config if the user doesn't already exist

debian/changelog

@@ -1,5 +1,6 @@
 livecd-rootfs (2.818) UNRELEASED; urgency=medium
 
+  [ Dave Jones ]
   * raspi: drop mkswap.service and swapfile.swap units in
     099-ubuntu-image-customization.chroot in favour of units provided by
     ubuntu-raspi-settings-desktop
@@ -8,6 +9,9 @@ livecd-rootfs (2.818) UNRELEASED; urgency=medium
   * raspi: drop growfs option from fstab in favour of growroot-almost
     service provided by ubuntu-raspi-settings-desktop
 
+  [ William 'jawn-smith' Wilson ]
+  * Skip oem-config setup in hooks if the oem user already exists.
+
  -- Dave Jones <dave.jones@canonical.com>  Tue, 28 Mar 2023 14:38:55 +0100
 
 livecd-rootfs (2.817) lunar; urgency=medium

live-build/ubuntu/hooks/099-ubuntu-image-customization.chroot

@@ -11,7 +11,13 @@ if [ "$IMAGEFORMAT" == "none" ]; then
         touch /var/log/syslog
         chown syslog:adm /var/log/syslog
 
-        # Create the oem user account
+        # Create the oem user account only if it doesn't already exist
+        if ! id "oem" &>/dev/null; then
+                /usr/sbin/useradd -d /home/oem -G adm,sudo -m -N -u 29999 oem
+                /usr/sbin/oem-config-prepare --quiet
+                touch "/var/lib/oem-config/run"
+        fi
+
         /usr/sbin/useradd -d /home/oem -G adm,sudo -m -N -u 29999 oem
 
         /usr/sbin/oem-config-prepare --quiet