Use userChanges instead of getContainer(0)

CURA-4916

cura/Settings/MachineManager.py

@@ -1494,5 +1494,5 @@ class MachineManager(QObject):
     @pyqtSlot(str, str, str)
     def setSettingForAllExtruders(self, setting_name: str, property_name: str, property_value: str):
         for key, extruder in self._global_container_stack.extruders.items():
-            container = extruder.getContainer(0)
+            container = extruder.userChanges
             container.setProperty(setting_name, property_name, property_value)