Donald Trump’s niece said on Wednesday that her uncle and his fans had a bad day, despite the fact that the Supreme Court agreed to hear the ex-president’s immunity claim. Mary Trump, a psychologist who just last week said Donald’s “untreated psychiatric condition” is worsening, focused in on her uncle’s legal problems in her Substack piece Wednesday evening. The post came the same day as the nation’s top court decided to take on Trump’s immunity appeal, a move some experts have warned plays into the criminal defendant’s hands. ALSO READ: Fox PAC gave big money to key Democrats “The Supreme Co…