MIAMI — Twenty-five migrants from Cuba came ashore on Key Biscayne early Tuesday, U.S. Border Patrol said. TV news showed a group of people sitting on the ground near the Crandon Park Marina. Miami-Dade police, Key Biscayne police and U.S. Border Patrol vehicles were there. U.S. Border Patrol agents took the migrants into custody. Since October, the U.S. Coast Guard has stopped at sea more than 3,000 Florida-bound Cuban migrants fleeing deteriorating economic, safety and political conditions on the island. That’s more than the last five fiscal years combined, according to the agency. More than…