Unable to create VMs with 44~beta.1-1ubuntu1

[J-P Nurmi]

Steps:
- run gnome-boxes
- create a new VM
- select file or download os

Expected result:
GNOME Boxes shows VM settings

Actual result:
The new VM dialog is stuck showing a spinner and the app prints a critical error:
```
(gnome-boxes:63557): Boxes-CRITICAL **: 07:39:29.306: boxes_installer_media_get_device_from_device_file: assertion 'client != NULL' failed
```

ProblemType: Bug
DistroRelease: Ubuntu 23.04
Package: gnome-boxes 44~beta.1-1ubuntu1
ProcVersionSignature: Ubuntu 5.19.0-29.30-generic 5.19.17
Uname: Linux 5.19.0-29-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.26.0-0ubuntu2
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Tue Feb 28 07:42:06 2023
InstallationDate: Installed on 2022-06-13 (259 days ago)
InstallationMedia: Ubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
SourcePackage: gnome-boxes
UpgradeStatus: Upgraded to lunar on 2023-01-30 (29 days ago)

[Launchpad Janitor (janitor)]

This bug was fixed in the package gnome-boxes - 44~rc-1ubuntu1

---------------
gnome-boxes (44~rc-1ubuntu1) lunar; urgency=medium

  * Merge with Debian. Remaining changes:
    - Update debian/gsettings-override & recommended-downloads.xml
      for Ubuntu
    - Use dh_migrations to remove the old cached Ubuntu logo

gnome-boxes (44~rc-1) experimental; urgency=medium

  * New upstream release
    - Fixes inability to create VMs with 44~beta.1 (LP: #2008759)

 -- Jeremy Bicha <email address hidden> Mon, 06 Mar 2023 16:30:19 -0500