TikTok has shaken up its senior ranks, replacing several senior executives including the person running its trust & safety unit, which handles content moderation, and appointing a protege of CEO Shou Zi Chew to oversee that part of the business, according to people at the company and a memo distributed to staff.The shakeup comes weeks after Chew testified before Congress about how TikTok deals with content that could be harmful for children, and suggests the executive is trying to take more cont...