The owner of the Sagamore Hotel in Miami Beach faces a $31.5 million foreclosure lawsuit filed by a commercial mortgage-backed securities (CMBS) fund. Built in 1948, the 93-room hotel, at 1671 Collins Ave., missed its last three mortgage payments, according to data from CMBS analysis firm Trepp. On Monday, JPMCC 2006 LDP7 Miami Beach, with LNR Corp….