Create dummy peerConnections without calling into WebRTC

[SystemKeeper]

Since https://github.com/nextcloud/talk-ios/blame/9afa32aa361077193cb776c6f4147a798f01026d/NextcloudTalk/Calls/NCCallController.m#L1526-L1533 we are creating peerConnections for every participant. On init we already call into the WebRTC lib to get the connection from the peerConnectionFactory. We should prevent that for dummy peers.

[SystemKeeper]

I think it’s a bit more complex here. We can only do that if we don’t have publishing rights and the other participant as well. Otherwise we loose data channel for speaker detection