[sddm-theme] KeyboardButton: Fix layout name not being shown
It used to cause an error like this:
[03:21:31.246] (WW) GREETER: file:///usr/share/sddm/themes/breeze/KeyboardButton.qml:19: TypeError: Cannot read property 'shortName' of null
It used to cause an error like this:
[03:21:31.246] (WW) GREETER: file:///usr/share/sddm/themes/breeze/KeyboardButton.qml:19: TypeError: Cannot read property 'shortName' of null