ubuntucinnamon-live task has existed for a while now, use it instead of hard-coded list of packages.

debian/changelog

@@ -1,6 +1,8 @@
 livecd-rootfs (23.10.33) UNRELEASED; urgency=medium
 
   * Drop references to kubuntu-plasma5, obsolete since wily
+  * ubuntucinnamon-live task has existed for a while now, use it instead of
+    hard-coded list of packages.
 
  -- Steve Langasek <steve.langasek@ubuntu.com>  Wed, 06 Sep 2023 11:23:17 -0700
 

live-build/auto/config

@@ -805,14 +805,7 @@ case $PROJECT in
 
 	ubuntucinnamon)
 		add_task install minimal standard ubuntucinnamon-desktop
-		# XXX: Adding live packages manually temporarily until we have
-		#  the live task for ubuntucinnamon set up properly.
-		add_package live ubiquity-frontend-gtk
-		add_package live ubiquity-ubuntu-artwork ubiquity-slideshow-ubuntu
-		add_package live gtk-im-libthai ibus-hangul ibus-mozc ibus-unikey
-		add_package live zfsutils-linux zfs-initramfs zsys
-		add_package live sssd realmd adcli
-		add_package live gparted cifs-utils
+		LIVE_TASK=ubuntucinnamon-live
 		KERNEL_FLAVOURS=generic
 		;;