[webrtc-pc] setConfiguration({ peerIdentity }) when there is no initial peerIdentity

soareschen has just created a new issue for https://github.com/w3c/webrtc-pc:

== setConfiguration({ peerIdentity }) when there is no initial peerIdentity ==
`setConfiguration` says:

>  If configuration.peerIdentity is set and its value differs from the target peer identity, throw an InvalidModificationError.

`setRemoteDescription` says

> The target peer identity cannot be changed once set.

If a peer connection is initially constructed without a `peerIdentity`, there is no target peer identity established, so it is not set. So when `setConfiguration()` is called with a new `peerIdentity`, is there error thrown?

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/1456 using your GitHub account