Some documentaries observe their subjects, some documentaries interrogate them, and then there is “You Can See Everything,” Nathan Fielder and Lance Oppenheim’s surreal, extraordinary new Elizabeth Holmes film, a work that keeps destabilizing the very idea that observation can ever produce something as reassuring as objective truth. So slippery, funny, unnerving, and formally audacious, it can leave you so disoriented you feel as if you’ve been …