SPRINGFIELD – Republicans in the Illinois House on Thursday unveiled a single charge they hope to bring against Democratic House Speaker Michael J. Madigan, accusing him of “conduct unbecoming to a legislator or which constitutes a breach of public trust.” House Minority Leader James B. Durkin, R-Western Springs, introduced that charge during the first day of hearings of a special investigative committee that is looking into Madigan’s role in a bribery and extortion scheme involving utility giant Commonwealth Edison.“As …