Update field_order to be an optional list

src/backend/langflow/interface/custom/custom_component/custom_component.py

@@ -33,7 +33,7 @@ class CustomComponent(Component):
     """The code of the component. Defaults to None."""
     field_config: dict = {}
     """The field configuration of the component. Defaults to an empty dictionary."""
-    field_order: List[str] = []
+    field_order: Optional[List[str]] = None
     """The field order of the component. Defaults to an empty list."""
     code_class_base_inheritance: ClassVar[str] = "CustomComponent"
     function_entrypoint_name: ClassVar[str] = "build"
@@ -64,6 +64,9 @@ class CustomComponent(Component):
         flow_id, file_name = path.split("/", 1)
         return storage_svc.build_full_path(flow_id, file_name)
 
+    def _get_field_order(self):
+        return self.field_order or list(self.field_config.keys())
+
     def custom_repr(self):
         if self.repr_value == "":
             self.repr_value = self.status