community[patch]: Invoke callback prior to yielding token fix for HuggingFaceEndpoint (#20366)

- [x] **PR title**: community[patch]: Invoke callback prior to yielding
token fix for HuggingFaceEndpoint


- [x] **PR message**: 
- **Description:** Invoke callback prior to yielding token in stream
method in community HuggingFaceEndpoint
    - **Issue:** https://github.com/langchain-ai/langchain/issues/16913
    - **Dependencies:** None
    - **Twitter handle:** @bolun_zhang

If no one reviews your PR within a few days, please @-mention one of
baskaryan, efriis, eyurtsev, hwchase17.

---------

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

libs/community/langchain_community/llms/huggingface_endpoint.py

@@ -326,9 +326,10 @@ class HuggingFaceEndpoint(LLM):
             # yield text, if any
             if text:
                 chunk = GenerationChunk(text=text)
-                yield chunk
+
                 if run_manager:
                     run_manager.on_llm_new_token(chunk.text)
+                yield chunk
 
             # break if stop sequence found
             if stop_seq_found:
@@ -361,9 +362,10 @@ class HuggingFaceEndpoint(LLM):
             # yield text, if any
             if text:
                 chunk = GenerationChunk(text=text)
-                yield chunk
+
                 if run_manager:
                     await run_manager.on_llm_new_token(chunk.text)
+                yield chunk
 
             # break if stop sequence found
             if stop_seq_found: