Fix setting extruder definition in user changes container

cura/Settings/CuraStackBuilder.py

@@ -108,7 +108,7 @@ class CuraStackBuilder:
         user_container.addMetaDataEntry("extruder", new_stack_id)
         from cura.CuraApplication import CuraApplication
         user_container.addMetaDataEntry("setting_version", CuraApplication.SettingVersion)
-        user_container.setDefinition(machine_definition)
+        user_container.setDefinition(definition)
 
         stack.setUserChanges(user_container)
 

cura/Settings/MachineManager.py

@@ -772,7 +772,6 @@ class MachineManager(QObject):
                                         quality_manager.getWholeMachineDefinition(material_container.getDefinition()),
                                         [material_container])
 
-
             if not candidate_quality or isinstance(candidate_quality, type(self._empty_quality_changes_container)):
                 Logger.log("d", "Attempting to find fallback quality")
                 # Fall back to a quality (which must be compatible with all other extruders)

plugins/3MFReader/ThreeMFWorkspaceReader.py

@@ -768,6 +768,7 @@ class ThreeMFWorkspaceReader(WorkspaceReader):
                 self._container_registry.removeContainer(container.getId())
             return
 
+
         # Check quality profiles to make sure that if one stack has the "not supported" quality profile,
         # all others should have the same.
         #