If a 24-year-old shoe salesman slips away from a science museum’s ugly-sweater party and breaks into a closed exhibition of terra-cotta warriors, it is entirely possible that nothing bad will happen. Or he could steal a warrior’s thumb. After the salesman, Michael Rohana, confessed to doing that in Philadelphia six years ago, federal prosecutors sought a conviction on felony charges that could have put him in prison for decades. A jury was unable to reach a verdict in 2019, but his case is now heading for a resolution after a…