Field instant_answer_used gone

{
  "schema_fingerprint.metadata_keys": [
    "can_save",
    "citations",
    "content_references",
    "conversation_followup_suggestions_eligible",
    "cot_version",
    "default_model_slug",
    "finish_details",
    "is_complete",
    "is_visually_hidden_from_conversation",
    "message_source",
    "message_type",
    "model_slug",
    "model_switcher_deny",
    "parent_id",
    "request_id",
    "resolved_model_slug",
    "search_result_groups",
    "selected_sources",
    "serialization_metadata",
    "story_events",
    "turn_exchange_id",
    "working_turn_id"
  ]
}