DGDS: dragon: "Maybe save before arcade" reappears after saving and loading

[mduggan]

Before the arcade sequences in Rise of the Dragon, a dialog saying you should maybe save your game appears.

If we do save at that point, restoring the game still displays that dialog. You have to answer no to clear it.

This is a pretty minor annoyance but would be nice to fix. We may need a special case here to clear the dialog before saving.