Remove unused import
Remove unused import

This was for debugging, and I forgot to remove it.

Contributes to issue CURA-3903.

alephobjects/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,alephobjects/CuraEngine,ROBO3D/CuraEngine,Ultimaker/CuraEngine,ROBO3D/CuraEngine,Ultimaker/CuraEngine