json mode standard test (#25497)

Co-authored-by: Chester Curme <chester.curme@gmail.com>

libs/partners/mistralai/tests/integration_tests/test_standard.py

@@ -19,6 +19,10 @@ class TestMistralStandard(ChatModelIntegrationTests):
     def chat_model_params(self) -> dict:
         return {"model": "mistral-large-latest", "temperature": 0}
 
+    @property
+    def supports_json_mode(self) -> bool:
+        return True
+
     @property
     def tool_choice_value(self) -> Optional[str]:
         """Value to use for tool choice when used in tests."""