plasmoid: Show busy indicator while printing
Makes it easier to spot which printer is currently printing in a list of printers.
We should fix the enum situation but the magic number is consistent with its surroundings (4 being active, 5 being busy)
I have four printers in the list and I assume an office will have some more. Not 100% convinced since it probably shows when someone else prints on a shared printer, too, but particularly with the job queue in the plasmoid, would be handy to find the printer quickly.