Bari Weiss — the 41-year-old “it girl” journalist who just became CBS News’ editor in chief — faces a “snake pit” as she looks to reshape the left-leaning network, sources told The Post. Paramount Skydance boss David Ellison said Monday that he wants to restore “balance” to CBS News and its marquee shows — “60 Minutes,” “Face The Nation” and “CBS Sunday Morning” as he confirmed his hire of Weiss and the $150 million acquisition of her scrappy news site, The Free Press. But current and former