By Ben Aris in Berlin The sanctioned sister of Russian billionaire Alisher Usmanov has voluntarily and irrevocably waived her right to receive benefits from two family trusts set up years ago by the Uzbek-born tycoon, her representatives told bne IntelliNews, after earlier claims about her links to the trusts resulted in her being placed under Western sanctions. The move comes as Usmanov and his sister continue to challenge their listings in an EU court. Representatives of Gulbakhor Ismailova told bne IntelliNews she has signed deeds of exclusion that prevent her from receiving any future bene…