The Fitbit Flyer is ready to be thrashed.Image: lili sams/mashable Fitbit has a surprising new release coming out later this fall: a set of workout-ready wireless headphones called the Fitbit Flyer. The Flyer is Fitbit’s first product without any sensors or fitness-tracking features, a significant departure from the company’s signature line of largely wrist-based activity trackers. The Flyer is closely tied to the company’s other big fall release, the Ionic…