Princess Beatrice will “definitely help” the Royal Family as she provides crucial backup for the Firm, royal sources have claimed. The Princess of York was a key attendee at Prince William’s Buckingham Palace garden party earlier this week, where she stunned in a pink Beulah London dress. The 35-year-old took pictures with fans as she stopped by the prestigious event, which was also attended by Princess Eugenie, Zara Tindall, Mike Tindall and Peter Phillips. According to a royal insider, Prince William wanted to invite his cousins to bring some “excitement” to the Royal Family. A Palace source…