A former member of top South Korean girl group f (x), who had spoken out against cyberbullying, was found dead on Monday, police said.The body of Choi Jin-ri, better known by her stage name Sulli, 25, was discovered at her home in Seongnam, south of the capital, Seoul, police said.“Her manager visited her home after failing to reach her since their last call the night before,” police said in a statement.Sulli was grappling with severe depression, police said. They did not elaborate.How the K…