[3dprinter-general] Bug#1108760: slic3r-prusa: autopkgtest fails with autopkgtest version 5.48

[Gregor Riepl]

>   62s [2025-06-23 05:05:37.778952] [0x00007f7696ffd6c0] [error]   DBus 
> Connection Error: Failed to connect to socket /run/user/0/bus: 
> Permission denied

I believe the easiest fix for this would be to just run the test script in its own DBus session.

Replacing line 32 of check-gui with the following should do the trick:

dbus-run-session -- xvfb-run bash -c '