A Brooklyn high school teacher was arrested this week for allegedly groping a 16-year-old girl while calling her “beautiful,” cops and sources said.  Steven Schnee, 48, was busted Wednesday afternoon for allegedly touching the teen inappropriately on her leg at the Lafayette Educational Complex on Benson Avenue near Bay 43rd Street in Gravesend, according to authorities and sources. He allegedly told the teen, “You’re beautiful” and “I like your butt” during the disturbing incident, the sources