Update: Additional comments in a statement from Sen. Silverstein were added to the seventh and eighth from last paragraphs. SPRINGFIELD — Nearly three months after harassment allegations surfaced against a sitting lawmaker, a legislative inspector general office’s probe has found them unproven. A report has determined Sen. Ira I. Silverstein, a Democrat from Chicago, did not sexually harass a victim’s rights advocate while he was shepherding her bill through the Senate.Denise Rotheimer, who was …