Dec. 1 (UPI) -- Apple's artificial intelligence chief is stepping down, the company announced Monday in an AI leadership shakeup over Siri delays, as the iPhone maker vowed to "strengthen its commitment to shaping the future of AI for users everywhere." John Giannandrea, who has served as Apple's senior vice president for Machine Learning and AI Strategy since 2018, will serve as an adviser to the company before retiring next spring . "We are thankful for the role John played in building and