President Donald Trump's assistant, Natalie Harp, is about as devoted as flunkies can get, but a psychologist reveals that even Harp has her limits — and if crossed, she could do enormous damage to the president.“Harp, 35, has dominated several news cycles with her shocking loyalty to the president, which has at times bordered on creepy. As a reward for her never-ending fealty, the president has granted her access to meetings and people that a n…