Use only the active extruders when sending slice message

Fixes #5671

plugins/CuraEngineBackend/StartSliceJob.py

@@ -256,10 +256,7 @@ class StartSliceJob(Job):
             self._buildGlobalInheritsStackMessage(stack)
 
             # Build messages for extruder stacks
-            # Send the extruder settings in the order of extruder positions. Somehow, if you send e.g. extruder 3 first,
-            # then CuraEngine can slice with the wrong settings. This I think should be fixed in CuraEngine as well.
-            extruder_stack_list = sorted(list(global_stack.extruders.items()), key = lambda item: int(item[0]))
-            for _, extruder_stack in extruder_stack_list:
+            for extruder_stack in global_stack.extruderList:
                 self._buildExtruderMessage(extruder_stack)
 
             for group in filtered_object_groups: