Russian teenager Kamila Valieva will be allowed to take part in Sunday’s figure skating gala exhibition at the Beijing Olympics if she wins a medal in the women’s singles, state news agency Tass reported on Wednesday. The 15-year-old has been allowed to continue competing at the Winter Games by the Court of Arbitration for Sport (CAS) despite returning a positive doping test from December 25 for banned heart drug trimetazidine. She already helped the Russians to team gold last week and leads the individual standings heading into Thursday’s free programme. The International Olympic Committee (I…