May 2 (Reuters) - TikTok said on Tuesday its head of U.S. trust and safety, Eric Han, will depart the company on May 12, leaving the popular short-form video app without a key executive as it fights the threat of a ban in the U.S. TikTok, which is owned by Chinese tech company ByteDance, has already been banned from government-issued phones in countries such as Canada and Australia over concerns about whether the Chinese government can access user data or influence what people see on the popular app. It also faces calls from some U.S. lawmakers to ban the app...