Fix bug in FakeHumanExecution (#1102)

## Description:

Fix a bug causing an exception to be thrown which crashes the game.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [ ] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>

src/core/execution/FakeHumanExecution.ts

@@ -470,6 +470,7 @@ export class FakeHumanExecution implements Execution {
             this.mg.isOceanShore(t),
           )
         : Array.from(this.player.tiles());
+    if (tiles.length === 0) return null;
     return this.random.randElement(tiles);
   }