The once sedate Upper East Side is suddenly sizzling as luxe home sales are surging after being cratered by the pandemic. More contracts for homes priced at $4 million and up were signed on the Upper East Side than in any other Manhattan neighborhood during the first week of November, according to a report compiled by Donna Olshan of Olshan Realty. Among the eye-popping deals were two penthouse units combined into one with an asking price of $66.5 million. The apartments are in The Bellemont, a condo building at 1165 Madison Ave. designed by famed architect Robert A.M. Stern. An undisclosed buyer snatched up what will become the 13,011-square-foot home…