In the middle of heavy banned-substance hubbub, Russia’s Kamila Valieva Thursday turned in her worst performance of the games. Valieva fell several times and finished fourth in the women’s free skate competition. The 15-year-old fell on two quad attempts while also losing balance in at least four other instances. Her country-mates Anna Shcherbakova and Alexandra Trusova won gold and silver medals, respectively. Japan’s Kaori Sakamoto took the bronze. On Monday, she was cleared to continue competing at the Winter Olympics. However, regardless of her finish, Valieva nor any of her teammates will…