WASHINGTON — President Donald Trump’s personal assistant, John McEntee, lost his White House job this week because an investigation found he was a frequent gambler whose habit posed a security risk, according to two people familiar with his departure. Chip Somodevilla, Getty ImagesJohn McEntee, left, was President Donald Trump’s personal aide. A background investigation found that McEntee bet tens of thousands of dollars at a time, making him unsuitable for a sensitive position close to the president, according to a person with knowledge of the situation.