SHANGHAI/BEIJING — Tesla operated its Shanghai plant well below capacity on Tuesday, showing the problems factories face in trying to ramp up production under a strict COVID lockdown, while the Chinese capital Beijing has continued to struggle with a small but elusive outbreak. Many of the many companies that have reopened factories in Shanghai in recent weeks have struggled to get production lines up and running and keeping staff in a “closed loop” system. Even if they manage to do everything right, those corporations have suppliers that face challenges. The latest sign of struggle with higher production under COVID regulations…