https://medium.com/bloomberg/women-havent-given-up-on-sheryl-sandberg-44fe50060d28 > Photo: Jonathan Leibson/Getty Images for AOLBy Rebecca Greenfield > For the last decade, the gathering of the global elite at Davos has been a safe space for Sheryl Sandberg. This year, though, fresh off a bruising 2018, the Facebook COO arrived in the Alps on the defensive, apologizing…