Comment 11 for bug 1761014

I'm affected by this bug, and I am unable to install any packages due to it. Is there something I can do to resolve this, outside of a fresh install?
I'm on a minimal install of 18.04, which was up to date as of 4 days ago.

sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  gnome-themes-standard libdleyna-core-1.0-3 libgssdp-1.0-3 libgupnp-1.0-4 libmhash2
Use 'sudo apt autoremove' to remove them.
0 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.
2 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up gnome-session (3.28.1-0ubuntu3) ...
update-alternatives: error: cannot stat file '/etc/alternatives/gdm3.css': Invalid argument
dpkg: error processing package gnome-session (--configure):
 installed gnome-session package post-installation script subprocess returned error exit status 2
dpkg: dependency problems prevent configuration of ubuntu-gnome-desktop:
 ubuntu-gnome-desktop depends on gnome-session; however:
  Package gnome-session is not configured yet.

dpkg: error processing package ubuntu-gnome-desktop (--configure):
 dependency problems - leaving unconfigured
No apport report written because the error message indicates it's a follow-up error from a previous failure.
                                                                                                            Errors were encountered while processing:
 gnome-session
 ubuntu-gnome-desktop
E: Sub-process /usr/bin/dpkg returned an error code (1)