installer crashes in vm install

[Matthias Martin]

* install in Proxmox, using UEFI with no secure boot
* 8GB RAM, 16GB Diskspace
* LVM with encryption
crashed after all the usual questions were asked (after TZ selection).

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: ubiquity 22.04.20
ProcVersionSignature: Ubuntu 6.2.0-26.26~22.04.1-generic 6.2.13
Uname: Linux 6.2.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.470.2
CurrentDesktop: ubuntu:GNOME
Date: Wed Nov 22 19:13:18 2023
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 22.04.3 LTS "Jammy Jellyfish" - Release amd64 (20230807.2)
ProcEnviron:
 LANGUAGE=de_CH.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_CH.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)