Removed the dependency of the DiscoveredCloudPrintersModel on CloudOutputDevice,
which is Ultimaker specific. This can allow even external plugins to add to this
model in the future.
CURA-7022
Have a separate model to hold the discovered ultimaker cloud printers.
This model will be used to communicate across the application that new
cloud printers have been found which they weren't seen before.
CURA-7022
I don't know what exactly caused this since it's impossible to trace. But the crash happened with a setting called 'dual_gcode' which currently doesn't exist in Cura. So I think it must be some plug-in that adds it. In any case, it's good to be defensive about this sort of thing. Good type checking would've caught this for us.
Fixes Sentry issue CURA-JB.
See CURA-3M in sentry. It most commonly happens with the anycubic,
since it had some weird stuff with it suddenly supporting materials.
This change will make it so that no crash happens. Old profiles will still have
an empty material. This isn't really an issue, since the interface will mark this
as an error (prompting users to switch).
The PrintInformation test wasn't cleaning up after itself correclty. This
left some stuff behind that the other tests were using. Since this is bad (as at that point
tests can influence other tests), i've fixed that
This should not happen, but we've seen some cases where it would cause a crash, usually
when a previous upgrade did something a bit weird (in this specific case; a printer
with an empty variant, whereas it should have a variant).
Since any change that the user will make will ensure that the variant is no longer empty (eg;
any selection of a variant will mean it's no longer empty) and that there is no way back,
it should be pretty safe to ignore the situation as it will resolve itself eventually
CURA-6992
Conflicts:
cura/Machines/MaterialManager.py -> File was deleted in Master but I changed things for the lazy loading.
cura/Machines/Models/BaseMaterialsModel.py -> I clarified documentation on a line above a place where a timer was added in between.
Contributes to issue CURA-6793.
