Function parseDialMessage

Returns
    | {
        call_id: string;
        direction: "inbound"
        | "outbound";
        from: string;
        instruction?: string | null;
        language?: string | null;
        to: string;
        type: "call_connected";
    }
    | {
        transcript: { content: string; role: "agent"
        | "user" }[];
        type: "transcript_update";
    }
    | {
        response_id: number;
        transcript: { content: string; role: "agent"
        | "user" }[];
        type: "response_required";
    }
    | {
        response_id: number;
        transcript: { content: string; role: "agent"
        | "user" }[];
        type: "reminder_required";
    }
    | { timestamp: number; type: "ping_pong" }