After an astronomical rise in its first day of trading, VinFast Auto Ltd. is now coming back to Earth — erasing a chunk of its billionaire founder’s fortune.The Vietnamese electric vehicle-maker has fallen sharply over the two most recent trading days in New York, eliminating more than half of the 255% gain it notched on Tuesday when it listed on the Nasdaq Global Select Market.At $46.4 billion, VinFast’s market capitalization is still just above that of General Motors Co. Chairman and founder Pham Nhat Vuong, who controls all...