Dennis Kaiser leaned out of the scissor lift to reach the trumpeting angel. He gently brushed a vacuum cleaner hosepipe along her outstretched arm. For a minute, the sculpture and the art handler formed similar silhouettes in the sun-drenched American Wing.One, carved of wood 120 years ago, was crafted at a time when the Industrial Revolution was transforming modern life. The other, as contemporary as could be, sucked up the accumulated dust of six months of coronavirus pandemic-required…