erase the type when storing nil []byte into map

Author: karlseguin

stmt.go

@@ -225,11 +225,16 @@ func (s *Stmt) MapInto(m map[string]any) error {
 			m[name] = s.ColumnDouble(i)
 			break
 		case C.SQLITE_BLOB:
-			var err error
-			m[name], err = s.ColumnBytes(i)
+			value, err := s.ColumnBytes(i)
 			if err != nil {
 				return err
 			}
+			// erase the type
+			if value == nil {
+				m[name] = nil
+			} else {
+				m[name] = value
+			}
 			break
 		}
 	}