MINNEAPOLIS — U.S. District Judge Michael Davis had seen this in his courtroom before — a young Somali-American who hadn’t previously been a troublemaker was now accused of conspiring to leave the U.S. and join the Islamic State group.The 6-foot-5 Davis, who can make defendants fidget with his long, drawn-out silences, stressed the gravity of the charges and tried to gauge whether this particular young man was truly dedicated to jihad or simply misguided and a possible candidate for rehabilitation.Federal …