Google co-founder Sergey Brin is buying a $50 million oceanfront home on Miami Beach’s Allison Island — but he won’t be able to dock his $450 million megayacht Dragonfly there. The new-construction dwelling was completed in 2019, according to city records. At just under 10,000 square feet, the property comes with 200 feet on the ocean and sits on just under an acre. The double lot is impressive, but the yacht — at 466 feet long — is more than double the width of the property. Brin’s offer for