Installer fails to initialise on Ubuntu MATE 24.04 daily

[Martin Wimpress ]

ubuntu-desktop-bootstrap doesn't start on Ubuntu MATE.

There is not currently an autostart for ubuntu-desktop-bootstrap yet, so the installer is started by double-clicking the desktop icon or running `ubuntu-desktop-bootstrap` from a terminal. Looking at stdout, it is endlessly waiting for `subiquity_server` to start.

As ubuntu-desktop-bootstrap starts, there are a few critical logs saying: Failed to read XDG desktop portal settings. xdg-desktop-portal-gtk is seeded in Ubuntu MATE.

[Ubuntu QA Website (ubuntuqa)]

This bug has been reported on the Ubuntu ISO testing tracker.

A list of all reports related to this bug can be found here:
http://iso.qa.ubuntu.com/qatracker/reports/bugs/2060405

[Martin Wimpress  (flexiondotorg)]

Added a screenshot of subquity_server failing to start on Ubuntu MATE.

[Martin Wimpress  (flexiondotorg)]

Thanks to some debugging by @fossfreedom, several packages are not present on the Ubuntu MATE image even though they are seeded. One example is `lvm2`.

@fossfreedom spotted that Ubuntu MATE is missing (but all other flavours are listed) in livecd-rootfs for the step that "Ensure that most things e.g. includes.chroot are copied as is"

https://git.launchpad.net/ubuntu/+source/livecd-rootfs/tree/live-build/auto/config#n1524

[Martin Wimpress  (flexiondotorg)]

The following might be related:

- https://bugs.launchpad.net/ubuntu/+source/livecd-rootfs/+bug/2058161

[Martin Wimpress  (flexiondotorg)]

Closing this as the root cause appears to be https://bugs.launchpad.net/ubuntu/+source/livecd-rootfs/+bug/2058161

Which should be fixed via: https://launchpad.net/ubuntu/+source/livecd-rootfs/24.04.57