JEFFERSON CITY, Mo. — Just months after Missouri voters approved stronger constitutional gun rights, the new amendment is being put to the test by a convicted drug dealer who is citing it as a reason why his former felony shouldn’t disqualify him from carrying a gun. The Missouri Supreme Court is to hear arguments Tuesday on whether the new constitutional provision subjecting gun-control laws to strict legal scrutiny means that Missouri can no longer bar no-nviolent felons from possessing firearms. In an …