Fix test_specification_editor_window

There was a wrong signature in a mock lambda

Re #2294

tests/project_item/test_specification_editor_window.py

@@ -155,7 +155,7 @@ def test_rename_specification_for_item(self):
             project_item.set_specification(specification)
             self._toolbox.project().add_item(project_item)
             window = SpecificationEditorWindowBase(self._toolbox, item=project_item)
-            mock_make_specification.side_effect = lambda name, exiting: ProjectItemSpecification(
+            mock_make_specification.side_effect = lambda name: ProjectItemSpecification(
                 name, window._spec_toolbar.description(), "Mock"
             )
             mock_save.return_value = {}