WASHINGTON (Reuters) -U.S. Defense Secretary Lloyd Austin is expected to leave military hospital later on Tuesday and will attend a Ukraine-related virtual meeting the next day, the Pentagon said, as the Pentagon chief struggles in the wake of prostate cancer surgery. It was the second time this year Austin, 70, was hospitalized - this time to address a bladder issue - since a December surgery to treat prostate cancer. He triggered a political uproar last month after failing to disclose his surg