The team captain wins the arena on behalf of the team.
When any of the team members claims victory for the arena the captain
accepts the gesture.

This is used when embeddeding platform views - we allow configuring a
set of gestures that should be forwarded to the platform view.
We add the set of gesture recognizers to a GestureArenaTeam with a
captain, and if the captain accepts the gesture we forward it to the
platform view.