fix: do not require peer id for webrtc-direct

[achingbrain]

We can get their peer id during the noise handshake, we do not need to have it in the multiaddr. We need it for regular webrtc as the SDP handshake happens via a relay, but that's not the case here.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation if necessary (this includes comments as well)
• I have added tests that prove my fix is effective or that my feature works