Is not a snap cgroup for all snaps in x2go sessions

[Michael Joyner]

Fresh install of xubuntu.

Installed stock x2goserver.

Connect to system and run XFCE desktop using default client desktop settings.

Attempting to run any app installed as a snap results in errors like the following:

```
$ dbeaver-ce
/user.slice/user-1000.slice/session-55.scope is not a snap cgroup
```

This also occurs for the default install of Firefox. I had to install a deb version to file this bug report.

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.04 LTS
Release: 22.04
Codename: jammy

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: x2goserver 4.1.0.3-5
ProcVersionSignature: Ubuntu 5.15.0-35.36-generic 5.15.35
Uname: Linux 5.15.0-35-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: pass
Date: Mon Jun 6 15:36:00 2022
InstallationDate: Installed on 2022-06-02 (4 days ago)
InstallationMedia: Xubuntu 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
SourcePackage: x2goserver
UpgradeStatus: No upgrade log present (probably fresh install)
modified.conffile..etc.sudoers.d.x2goserver: [inaccessible: [Errno 13] Permission denied: '/etc/sudoers.d/x2goserver']

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.