[Bug] Empty gym with no "Flee" button if last defender faints while re-joining group attack.

After selecting my 6 attackers, I clicked the button to fight the gym, but my teammate finished off the last defender right before it put me in the gym. The gym was empty (no defender and no attacker either), but had the normal "outside map" buttons on the bottom instead of the Flee / Switch buttons. With no way to exit the gym, I had to close and re-start the app.