CHICAGO — This was a somewhat ugly outing for the 76ers. They blew a 19-point lead. James Harden struggled mightily from the field. It took Tyrese Maxey a long time to find his rhythm due to early foul trouble. And Joel Embiid missed a pair of foul shots with 61 seconds remaining in a tied game. Yet the Sixers walked out of the United Center Saturday night with a cherished 114-109 victory thanks to Embiid’s late heroics. The All-Star center shook off the missed foul shots and buried a 25-foot three-pointer with 18.1 seconds left. Then on the ensuing possession, he made a defensive play at the …