Drop cargo-culted code for "preinstalled" images.

Somewhere along the line, we started trying to add packages to the live
environment of flavor "preinstalled" images.  But:

- we don't build preinstalled images for any flavors
- the preinstalled images for projects like cloud images and wsl are
  explicitly excepted from this code
- the only desktop project we do produce preinstalled images for, Ubuntu
  on Raspberry Pi, uses ubuntu-image for building so this code is never
  reached

debian/changelog

@@ -1,6 +1,7 @@
 livecd-rootfs (24.04.4) UNRELEASED; urgency=medium
 
   * Drop a few remaining 'legacy' references.
+  * Drop cargo-culted code for "preinstalled" images.
 
  -- Steve Langasek <steve.langasek@ubuntu.com>  Sun, 05 Nov 2023 15:53:37 +0200
 

live-build/auto/config

@@ -547,50 +547,6 @@ case $IMAGEFORMAT in
 		;;
 esac
 
-if [ "$PREINSTALLED" = "true" ]; then
-	# Touch a random file that we can refer back to during build,
-	# cause that's wildly hackish
-	touch config/universe-enabled
-	case $PROJECT in
-		kubuntu*)
-			add_package live oem-config-kde ubiquity-frontend-kde
-			add_package live ubiquity-slideshow-kubuntu
-			;;
-		lubuntu*)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-lubuntu
-			;;
-		xubuntu*)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-xubuntu
-			;;
-		ubuntu-mate)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-ubuntu-mate
-			;;
-		ubuntu-unity)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-ubuntu
-			;;
-		ubuntu-server)
-			add_package live oem-config-debconf ubiquity-frontend-debconf
-			;;
-		ubuntu-base|ubuntu-oci|ubuntu-cpc|ubuntu-wsl|ubuntu-mini-iso)
-			;;
-		ubuntu)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-ubuntu
-			if [ "$SUBPROJECT" = "desktop-preinstalled" ]; then
-				add_package live language-pack-en-base oem-config-slideshow-ubuntu
-			fi
-			;;
-		*)
-			add_package live oem-config-gtk ubiquity-frontend-gtk
-			add_package live ubiquity-slideshow-ubuntu
-			;;
-	esac
-fi
-
 case $BINARYFORMAT in
 	iso*|usb*)
 		BINARY_IMAGES="$BINARYFORMAT"