Cutting ties! Sophie Turner and onetime sister-in-law Priyanka Chopra Jonas are no longer following each other on Instagram amid the former’s contentious divorce from Joe Jonas. “They used to be so close,” a source says of the Game of Thrones star, 27, and the Citadel actress, 41. “They confided in each other, called each other sissy, and now Priyanka’s allegiance lies with Joe and husband Nick.” Sophie’s loyalties have changed, too. After splitting from singer Joe, 34, in September, she turned to his ex-girlfriend, Taylor Swift, for support. They were seen grabbing dinner together in NYC and the pop star, 33, even loaned Sophie her Tribeca apartment while she and Joe worked out a temporary custody agreement for daughters Willa, 3, and Delphine, 15 months. “Divorcing Joe has forced Sophie…