Breaking news: Obama staffers are fixie-riding vegans. Or at least one of them is. I uncovered this total scoop at last night’s Young and the Guest List party, Washington Life magazine’s 4th annual oh-so-very exclusive affair to honor the most influential Washingtonians under 40. Invitees included Adrian Fenty and Jon Favreau, neither of whom showed up. But event organizers told me 15 Obama staffers had RSVP’d, so my goal for the night was to locate…