A former Teamsters union boss who was once one of the most powerful labor leaders in Chicago was sentenced Wednesday to 19 months in federal prison for extorting $325,000 from the head of a film studio in the city.The sentence comes more than three years after John Coli Sr. pleaded guilty to extortion, faced with secret recordings made by Cinespace Chicago Film Studios President Alex Pissios in which Coli could be heard threatening a union strike if Pissios didn’t pay him.In one tape, Coli tells Pissios that he would …