Princess Beatrice has been seen showing off her baby bump at a chic central London art fair this week. Just days after announcing she is expecting her second child with Edoardo Mapelli Mozzi, Beatrice was papped as she mingled with celebrities and sporting stars at Frieze, a high-profile art fair in the heart of the capital’s Regent’s Park. The event is billed as “the world’s leading platform for modern and contemporary art dedicated to artists, galleries, collectors and art lovers alike” – with attendees including tennis champion Emma Raducanu and Sherlock star Benedict Cumberbatch. And its L…