By Gabrielle Tétrault-Farber, Chang-Ran Kim and Julien Pretot BEIJING (Reuters) -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 that has rocked the Beijing 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 gave one last forced …
