[MNT]: in class cursor,when the mouse moves out of the ax, redrawing takes a long time

### Summary

https://github.com/matplotlib/matplotlib/blob/v3.10.1/lib/matplotlib/widgets.py#L1937
self.canvas.draw() takes a long time when mouse moves out

### Proposed fix

restore the background
self.canvas.restore_region(self.background)
self.canvas.blit(self.ax.bbox)