fix: mesh.layer_nr_max_filled_layer was set unsafe for multithreading (CURA-2747)
fix: mesh.layer_nr_max_filled_layer was set unsafe for multithreading (CURA-2747)

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