Amy Poehler says she’s not a real “over-sharer.” But the star of NBC’s Parks and Recreation did drop one bombshell “confession” at BookCon Saturday as she promoted her forthcoming, “Yes Please” before hundreds of fans. She got her job at Saturday Night Live back in 2001, she joked, the way most people do: “I slept with the head writer.” That, of course, was her pal Tina Fey.