“Schmigadoon” was all schmiles Sunday night. The Lorne Michaels-produced show , based on the canceled AppleTV+ series, won the all-important Tony Award for Best Musical at Radio City Music Hall. It badly needed it. Like most new musicals during this rough season, the comedy about a married couple who gets trapped inside an old-fashioned musical has had soft ticket sales in recent weeks. The top prize at the Tonys — the only one that really drives box office — should give it a helpful boost as