partners[minor]: Fix value error message for with_structured_output (#22877)

Currently, calling `with_structured_output()` with an invalid method
argument raises `Unrecognized method argument. Expected one of
'function_calling' or 'json_format'`, but the JSON mode option [is now
referred
to](https://python.langchain.com/v0.2/docs/how_to/structured_output/#the-with_structured_output-method)
by `'json_mode'`. This fixes that.

Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

libs/partners/fireworks/langchain_fireworks/chat_models.py

@@ -904,7 +904,7 @@ class ChatFireworks(BaseChatModel):
         else:
             raise ValueError(
                 f"Unrecognized method argument. Expected one of 'function_calling' or "
-                f"'json_format'. Received: '{method}'"
+                f"'json_mode'. Received: '{method}'"
             )
 
         if include_raw:

libs/partners/groq/langchain_groq/chat_models.py

@@ -1034,7 +1034,7 @@ class ChatGroq(BaseChatModel):
         else:
             raise ValueError(
                 f"Unrecognized method argument. Expected one of 'function_calling' or "
-                f"'json_format'. Received: '{method}'"
+                f"'json_mode'. Received: '{method}'"
             )
 
         if include_raw:

libs/partners/openai/langchain_openai/chat_models/base.py

@@ -1139,7 +1139,7 @@ class BaseChatOpenAI(BaseChatModel):
         else:
             raise ValueError(
                 f"Unrecognized method argument. Expected one of 'function_calling' or "
-                f"'json_format'. Received: '{method}'"
+                f"'json_mode'. Received: '{method}'"
             )
 
         if include_raw: