Refactor dump_json method to use model_dump_json

- Fix the `dump_json` method in the `ModelView` class to call `model_dump_json` instead of `model_dump`, ensuring consistency in JSON serialization.
- Added a new test case in `TestListModelView` to verify the functionality of `dump_json` and check for correct IP address serialization.

oxi/conf.py

@@ -23,7 +23,7 @@ class ModelView(Generic[TModel]):
     def dump_json(self) -> str:
         if isinstance(self._model, list):
             return json.dumps(
-                [item.model_dump(by_alias=True) for item in self._model],
+                [item.model_dump_json(by_alias=True) for item in self._model],
                 ensure_ascii=False,
             )
         return self._model.model_dump_json(by_alias=True)