WASHINGTON — The Obama-Biden administration was a charmed era for America’s tech companies — a moment when they were lionized as innovators, hailed as job creators and largely left alone.Now Joe Biden is coming back, this time as president. But times have changed. The halcyon days of an adoring Washington are unlikely to return when Biden takes the oath of office in January, with mounting legislative and regulatory challenges to the industry — including stronger enforcement of antitrust laws — nearly certain to outlast the …