JAKARTA, July 21 (Reuters) – After donning a blue Cinderella dress, Sind Yanti carefully arranges her pale yellow “hijab”, or traditional headscarf, vision costume into folds that resemble hair. She can express herself while preserving the Islamic requirement of modest dress for women, Yanti said. Fans hoping to dress like Joaquin Phoenix’s villainous title character when Joker hits theaters next weekend, won’t be able to do so at one major theater chain.