After a damning report about President Joe Biden’s mental fitness, one Republican is demanding what Democrats always wanted for former President Donald Trump: invoke the 25th Amendment. New York Republican Rep. Claudia Tenney sent a letter to Attorney General Merrick Garland on Thursday night asserting that she had “grave concerns” about Biden after Special Counsel Robert Hur’s “alarming” assessment of the president’s mental capacity. As the Tampa Free Press reported last week, Hur concluded that Biden did willfully and wrongfully keep classified materials, but that he should not be prosecuted…