Don't use printerConnected from Sidebar.qml
Don't use printerConnected from Sidebar.qml

We don't need it if we just check for connectedPrinter to not be null each time.

Contributes to issue CURA-3161.

fieldOfView/Cura,Curahelper/Cura,hmflash/Cura,ynotstartups/Wanhao,hmflash/Cura,Curahelper/Cura,fieldOfView/Cura,ynotstartups/Wanhao