SPRINGFIELD — A stunning federal indictment this week all but ensures that one of the more prominent politicians in this fall’s election won’t be on the ballot. But that likely won’t stop Republicans from using Michael Madigan’s grim-faced likeness in an effort to taint Democrats after the ex-House speaker was charged with 22 counts of racketeering and bribery.When he resigned a year ago, the Chicago Democrat was the longest serving legislative leader in U.S. history, with decades-long control …