Princess Beatrice was spotted for the first time since her pregnancy announcement leaving a celeb-stuffed London party. The 36-year-old was pictured leaving a party at the Chiltern Firehouse in central London, a popular spot for celebrities. Beatrice was dressed in a velvet blazer with a cinched waist and long sleeves. She paired the blazer with wide-leg trousers and glam make-up. She was attending the event in central London to mark the swanky restaurant’s 10th anniversary. Also in attendance was Noel Gallagher, who was partying just days after Oasis announced their first US dates in 16 years…