Another vehicle was stolen at gunpoint from a Downtown Jersey City commercial parking lot Sunday, 10 days after two cars were taken from the same lot in an armed robbery, authorities said. In both cases, the gunmen also took the parking attendant’s cell phone and cash, Jersey City spokeswoman Kimberly Wallace-Scalcione said. In the latest incident at 143 Christopher Columbus Drive, just before midnight, the assailants said they had a gun before stealing a BMW and the attendant’s personal items, Wallace-Scalcione said. No injuries were reported. Jersey City and other municipalities across the s…