BEIJING—Russian teenage figure skater Kamila Valieva tumbled to fourth place in the women’s singles event on Thursday, yielding to the pressure of a doping controversy at the Beijing Olympic Games. In a final twist that ensures a medal ceremony will go ahead on Friday, Valieva’s compatriots Anna Shcherbakova claimed the gold medal and Alexandra Trusova took the silver, while a beaming Kaori Sakamoto of Japan claimed the bronze medal. After stumbling to the ice more than once, 15-year-old Valieva masked her face with her hand as she skated head down towards the exit with her supporters shouting “Molodets!” “Molodets!” (Bravo, bravo). Decked out in a sparkling black and red dress and bright red gloves, the skating prodigy kept her composure for 30 seconds and landed her opening quadruple Salchow jump. But she then faltered after a triple Axel and made a number of uncharacteristic stumbles after that in a free …