As someone who has been playing Jam City's Harry Potter: Hogwarts Mystery from the beginning, it's a thrill to bring you this exclusive today. Back in April of this year, Jam City announced a fan design contest for the Portkey Games title that would allow players and aspiring fashionistas a chance to create a custom outfit for the game, one which would be available for players around the world to wear. Now, three finalists have been chosen from among the thousands of entries. Once Gryffindors, Hufflepuffs, Ravenclaws, and Slytherins vote on the finalists, the winner's outfit will …