Donald Trump might be president, but even he has to endure holiday dinners with his in-laws. Trump, 79, spent Christmas Eve at his Mar-a-Lago estate alongside family members including First Lady Melania Trump, 55, and her father, Viktor Knavs—who is just two years the president’s senior. The trio was seated together at an extravagant Christmas Eve dinner Wednesday night at the Palm Beach resort, which Forbes valued at $325 million in 2023. In…