MINNEAPOLIS — The former Minneapolis police officer who kneeled on George Floyd’s back while another officer kneeled on the Black man’s neck was sentenced Friday to 3 1/2 years in prison.J. Alexander Kueng pleaded guilty in October to a state count of aiding and abetting second-degree manslaughter. In exchange, a charge of aiding and abetting murder was dropped. Kueng is already serving a federal sentence for violating Floyd’s civil rights, and the state and federal sentence will be served at the …