WASHINGTON — With Amy Coney Barrett expected to join the Supreme Court as early as next week, the court’s action in a Pennsylvania voting case has heightened fears among Democrats about the court being asked to decide a post-election dispute and with it, the winner of the White House.The justices split 4-4 Monday over a Republican plea to undo a state court order and force elections officials to ignore absentee ballots received after Election Day, Nov. 3. The tie vote left the Pennsylvania court order in effect and allows …