Fix radius calculation for avoidance areas
Fix radius calculation for avoidance areas

The radii are slightly larger because it concerns a node on a lower layer.

Contributes to issue CURA-4523.

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