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.
