#8786 Fixed: Callback handler disconnect in between (#8787)

Fixes for  #8786 @agola11 

- Description: The flow of callback is breaking till the last chain, as
callbacks are missed in between chain along nested path. This will help
get full trace and correlate parent child relationship in all nested
chains.

  - Issue: the issue #8786 
  - Dependencies: NA
  - Tag maintainer: @agola11 
  - Twitter handle: Agarwal_Ankur

libs/langchain/langchain/chains/question_answering/__init__.py

@@ -83,6 +83,7 @@ def _load_stuff_chain(
         document_variable_name=document_variable_name,
         verbose=verbose,
         callback_manager=callback_manager,
+        callbacks=callbacks,
         **kwargs,
     )
 
@@ -209,6 +210,7 @@ def _load_refine_chain(
         initial_response_name=initial_response_name,
         verbose=verbose,
         callback_manager=callback_manager,
+        callbacks=callbacks,
         **kwargs,
     )