Adrienne Arsht, the prominent Miami philanthropist and attorney, on Friday sold her sprawling Coconut Grove estate overlooking Key Biscayne for $106.9 million, a record price in Miami-Dade County for a residential sale. The buyer of the four-acre Arsht Estate, which is nestled along the bayfront, wasn’t disclosed. Arsht, who formerly ran her family-owned TotalBank, is known for donating millions to several causes — most notably her namesake the county’s Adrienne Arsht Center for the Performing Arts. Although the property sale falls short of the $150 million asking price when it hit the market in January, it surpassed the peak set by hedge-fund billionaire Ken Griffin. Griffin, a Florida native, is…