saw tests pass locally with this change

src/spiffworkflow_backend/models/process_instance.py

@@ -53,20 +53,6 @@ class NavigationItemSchema(Schema):
         marshmallow.fields.Nested(lambda: NavigationItemSchema())
     )
 
-    @marshmallow.post_load
-    def make_nav(self, data: dict[str, Any], **kwargs: dict) -> NavItem:
-        """Make_nav."""
-        state = data.pop("state", None)
-        task_id = data.pop("task_id", None)
-        children = data.pop("children", [])
-        spec_type = data.pop("spec_type", None)
-        item = NavItem(**data)
-        item.state = state
-        item.task_id = task_id
-        item.children = children
-        item.spec_type = spec_type
-        return item
-
 
 class ProcessInstanceStatus(SpiffEnum):
     """ProcessInstanceStatus."""