A hit-and-run driver seriously injured Jasmine Vega and Sean Kramer around 2 a.m. on the Southwest Side of Chicago as they walked across Kedzie Avenue at 43rd Street — shortly after an allegedly truculent Uber driver ejected them from his vehicle at 44th Street and Homan Avenue, around a mile from their destination in the 4100 block of South Albany Avenue.Proximate causation was the high hurdle for claims by Kramer and Nancy Coronel, Vega’s guardian, against the Uber driver, Farid Kessanti, and Uber …