Only enable sanding line spacing when sanding is enabled
Only enable sanding line spacing when sanding is enabled

Forgot this one.

Contributes to issue CURA-3903.

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