A dancer in Madonna’s Celebration Tour fell while dragging the star in a chair mid-concert in Seattle on Sunday, sending the chair and the pop goddess tumbling to the floor. Madonna, 65, didn’t miss a note or a beat. Landing on her back, she quickly flipped onto her stomach, singing all the while, and finished belting out her line in “Open Your Heart to Me.” She then giggled and leaped to her feet, declining offers of assistance. In video posted on social media, Madonna was seen sitting in the chair as the dancer tilted it back and dragged it across the stage. He apparently lost his grip, thou…