SPRINGFIELD — A class action lawsuit filed this week against utility giant Commonwealth Edison seeks to recover potentially hundreds of millions of dollars for consumers who were charged rates under legislation that the company has admitted was aided by a bribery scheme involving Illinois House Speaker Michael J. Madigan.The suit, filed Monday in Cook County Circuit Court, accuses ComEd of violating the state’s Consumer Fraud and Deceptive Businesses Practices Act, which is designed to protect consumers against unfair …