No longer add material to qualityChanges

QualityChanges are never supposed to have Material.

CURA-3929

cura/Settings/ContainerManager.py

@@ -931,12 +931,6 @@ class ContainerManager(QObject):
             quality_changes.setDefinition(self._container_registry.findContainers(id = "fdmprinter")[0])
         else:
             quality_changes.setDefinition(QualityManager.getInstance().getParentMachineDefinition(machine_definition))
-            whole_machine_definition = QualityManager.getInstance().getWholeMachineDefinition(machine_definition)
-
-            if whole_machine_definition.getMetaDataEntry("has_materials"):
-                material = quality_container.getMetaDataEntry("material")
-                if material is not None:
-                    quality_changes.addMetaDataEntry("material", material)
 
         from cura.CuraApplication import CuraApplication
         quality_changes.addMetaDataEntry("setting_version", CuraApplication.SettingVersion)