Add a "New Board" button to the Game Over dialog in the Dungeon Crawler sample.

[zach-klippenstein]

Originally posted by @zach-klippenstein in square/workflow#874 (comment)

[lpizzinidev]

Hi ✋ Is the issue still up for grabs?

[rjrjr]

Sure! If you take it on, please work against the ray/ui-update branch, https://github.com/square/workflow-kotlin/tree/ray/ui-update

[lpizzinidev]

👍 Ok!
Just one question, to make sure that I implement it correctly.
With the click of the "New Board" button, the board selection screen should be shown to the player?

[rjrjr]

Yes please.

[lpizzinidev]

👍 I'll work on this