TALLAHASSEE — A last-minute push to block former Miami Mayor Manny Diaz from clinching the chairmanship of the Florida Democratic Party is taking shape just a day before he is expected to secure the post amid a flurry of high-profile endorsements. Diaz, a prominent Miami Cuban, made a splashy entrance into the race in late November, bringing in a handful of well-known staffers, and endorsements ranging from former New York City Mayor Michael Bloomberg, a billionaire who spent $100 million in Florida during the 2020 election cycle, and South Florida billionaire Jorge Pérez. He has since been endorsed by dozens of Florida Democratic politicians.