Elixir WebRTC: Missing DTLS peer fingerprint validation in ex_webrtc client-role handshake

Elixir WebRTC is an Elixir implementation of the W3C WebRTC API. Prior to 0.15.1 and 0.16.1, missing DTLS peer certificate fingerprint validation in the DTLS client (active) role removes one side of WebRTC's mutual authentication. The bug is not independently exploitable for media interception in standard deployments, but enables a full man-in-the-middle attack when chained with insecure signalling or a peer with similar validation gaps. This vulnerability is fixed in 0.15.1 and 0.16.1.