Connect to function, not result of function
Connect to function, not result of function

The result of the function was None, but I don't need None to be called whenever extruders changed. I need the function itself to be called.

Contributes to issues CURA-1278 and CURA-351.

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