Prince William reportedly won’t participate in any films about his late mother, Princess Diana, as rumors swirl that Prince Harry has plans for a documentary. The Prince of Wales declined “several offers to make or appear in documentary tributes” about his mother as the date approaches to mark the 30th anniversary of her death, according to the Times. The outlet reported that William, 44, wants to avoid a situation where he and his estranged brother, Harry, are “pitted against each other” during film-making. The future king reportedly believes that his tributes for Diana’s 20th death anniversary in 2017 were his public “catharsis.”…