Build the QA payload for the prompt.
Args:
app_name (str): Name of the app.
retriever (VectorStoreRetriever): Retriever instance.
question (str): Question asked in the prompt.
answer (str): Answer generated by the model.
auth_context (Optional[AuthContext]): Authentication context.
docs (List[Document]): List of documents retrieved.
prompt_entities (Dict[str, Any]): Entities present in the prompt.
prompt_time (str): Time when the prompt was generated.
prompt_gov_enabled (bool): Whether prompt governance is enabled.