fix: Install required package fuse3 when preseeding snaps (LP: #2031640)

fuse3 was previously installed through recommends but with minimized images we no longer install recommends packages.

It is only required when preseeding snaps so does not need to be present in all minimized images so does not
need to be in the cloud-minimal seed.

debian/changelog

@@ -3,6 +3,7 @@ livecd-rootfs (23.10.16) mantic; urgency=medium
   * fix: Do not install recommends for ubuntu-cpc minimized project (LP: #2031640)
   * fix: Remove dangling symlink /boot/initrd.img.old if exists (LP: #2031640)
   * fix: Ensure required dependencies are installed before trying `grub-install` (LP: #2031640)
+  * fix: Install required package fuse3 when preseeding snaps (LP: #2031640)
 
  -- Philip Roche <phil.roche@ubuntu.com>  Thu, 17 Aug 2023 11:44:23 +0100
 

live-build/functions

@@ -708,6 +708,12 @@ snap_preseed() {
     SNAP=${SNAP%=*}
     # strip /classic confinement
     local SNAP_NAME=${SNAP%/*}
+
+    # For snap preseed to work, we need to ensure that fuse3 is installed in the chroot.
+    # fuse3 is a recommends of snapd but if this is a minimized image then recommends are not installed
+    # and preseeding will fail.
+    chroot "${CHROOT_ROOT}" apt-get install --assume-yes --no-install-recommends fuse3
+
     # Seed from the specified channel (e.g. core18 latest/stable)
     # Or Channel endcoded in the snap name (e.g. lxd=4.0/stable/ubuntu-20.04)
     # Or Ubuntu policy default channel latest/stable/ubuntu-$(release_ver)