Fix error message when not connected in preheatUpdateTimer
Fix error message when not connected in preheatUpdateTimer

Can't get preheatBedRemainingTime from null.

Contributes to issue CURA-3161.

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