By Steve Holland WASHINGTON, July 25 (Reuters) - Jared Kushner, a former senior aide to then-President Donald Trump who is married to Trump's daughter, Ivanka, wrote in a memoir to be published next month that he had a bout with thyroid cancer in 2019 that was previously undisclosed. According to excerpts of the book seen by Reuters, Kushner wrote that White House physician Sean Conley pulled him aside on...