When it comes to the roll-out of next-generation 5G cellular technology, few regions in the world could be as excited as Southeast Asia, a region famed for intensive smartphone use.But this week’s dramatic escalation in the United States’ crackdown on Chinese telecoms giant Huawei has been a cold shower for those anticipating the mass-market arrival of a technology hyped as heralding a new dawn of driverless cars and artificial intelligence.Just weeks ago, Huawei had seemed assured of playing a…