[BUG] Changing keybinding for tracking demigod to empty will crash the game

When I have a keybinding for tracking demigod (default key is T) and change it when playing a game to nothing. The game will crash when using the T key

Reproduce:

- start demigod

- make sure the keybinding is set to T

- start a game

- go to options -> keys

- change the track demigod key to nothing by pressing the S key (which binding can not be changed)

- continue game

- press  any key

A crash to desktop will be the result

The problem exists because normally the window can not be left if a action is not bound. But it can be left after a unselectable key was pressed.