This was necessary after mutter configured a non-root user
for the image, although as it turned out not sufficient.
The latest image no longer sets up a special user, so building
the toolbox image should work again as before.
This reverts commit ee384d85da.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2813>
Toolbox is a convenient option for development, but setting up
the image with all dependencies is annoying at best, in particular
later in the cycle when `dnf builddep` is likely insufficient.
To address that, produce toolbox images for main and stable branches
that are based on the regular CI image, and update them whenever
the image version is updated. This guarantees that all build- and
runtime dependencies are included.
Unsurprisingly, the script that produces the image draws heavily
from freedesktop's ci-templates. The most notable difference
(other than being neither distro-agnostic nor generic) is that
tag names are fixed (toolbox:main, toolbox:43 etc.) to make them
easier to consume.
Instead, whether an image needs rebuilding is based on a custom
label that records the base image that was used.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2713>
