Moments after Apple’s Face ID demo face-planted in front of millions of viewers during its annual product unveiling, the company’s stock took a sharp dive.The drop from around $163 a share to $159 a share — its lowest point on what should have been a banner day — took place right after Craig Federighi, Apple’s senior vp of software engineering, came onstage to demo the new technology but failed to unlock the phone on the first try.Correlation? Causation? Hard to know — especially when you can’t get your phone unlocked to check.