langchain_groq[patch]: Invoke callback prior to yielding token (#18272)

## PR title
langchain_groq[patch]: Invoke callback prior to yielding

## PR message
**Description:**Invoke callback prior to yielding token in _stream and
_astream methods for groq.
Issue: https://github.com/langchain-ai/langchain/issues/16913
Dependencies: None
Twitter handle: None

libs/partners/groq/langchain_groq/chat_models.py

@@ -274,9 +274,10 @@ class ChatGroq(BaseChatModel):
             chunk = ChatGenerationChunk(
                 message=chunk, generation_info=generation_info or None
             )
-            yield chunk
+
             if run_manager:
                 run_manager.on_llm_new_token(chunk.text, chunk=chunk, logprobs=logprobs)
+            yield chunk
 
     async def _astream(
         self,
@@ -310,11 +311,12 @@ class ChatGroq(BaseChatModel):
             chunk = ChatGenerationChunk(
                 message=chunk, generation_info=generation_info or None
             )
-            yield chunk
+
             if run_manager:
                 await run_manager.on_llm_new_token(
                     token=chunk.text, chunk=chunk, logprobs=logprobs
                 )
+            yield chunk
 
     #
     # Internal methods