joinGroup method
Joining a group
If a player joins a public group they immediately become a member, but if they try and join a private group they must be accepted by a group admin.
Players can join a group.
Implementation
@override
Future<void> joinGroup({
required model.Session session,
required String groupId,
}) async {
await _client.joinGroup(
api.JoinGroupRequest(groupId: groupId),
options: _getSessionCallOptions(session),
);
}