virtualbox-guest-x11 does not work if user shell is zsh

[Eduardo]

virtualbox-guest-x11 does not work if user shell is set to /bin/zsh

Steps to reproduce:
1. Install ubuntu in a virtualbox
2. Install virtualbox-guest-x11
3. Reboot
4. Resizing works as expected
5. Install zsh and run chsh -s /bin/zsh <username>
6. Reboot
7. Resizing does not longer work

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: virtualbox-guest-x11 6.1.26-dfsg-4
ProcVersionSignature: Ubuntu 5.13.0-21.21-generic 5.13.18
Uname: Linux 5.13.0-21-generic x86_64
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: KDE
Date: Sun Nov 21 15:51:11 2021
InstallationDate: Installed on 2021-11-20 (0 days ago)
InstallationMedia: Kubuntu 21.10 "Impish Indri" - Release amd64 (20211012)
SourcePackage: virtualbox
UpgradeStatus: No upgrade log present (probably fresh install)