The Cook County Board Finance Committee approved a $3 million settlement Wednesday in a federal class-action lawsuit over delayed dental treatment at the county jail, as similar litigation continues in another case.U.S. District Judge Matthew F. Kennelly approved the settlement on Aug. 5, but the committee’s approval was the last step in finalizing the settlement agreement. The case is Demetrius Whitney v. Fauzia Khan, Thomas Dart and Cook County, 18-cv-4475.Separately, on Monday, U.S. District Judge Andrea R. Wood …