Tesla celebrated a historic first on Friday when a new Model Y left the factory in Austin and—without anyone in the vehicle—drove itself to a waiting customer a half-hour away. Already the second milestone this week after the commercial deployment of his robotaxi service, it marks an early birthday present for CEO Elon Musk. The entrepreneur had promised it to Tesla supporters for June 28, which is coincidentally when he turns 54 years old. “The first fully autonomous delivery of a Tes...