[RN] export RTCIceCandidate

Required for P2P.

react/features/base/lib-jitsi-meet/native/polyfills-webrtc.js

     MediaStream,
     MediaStreamTrack,
     RTCSessionDescription,
+    RTCIceCandidate,
     getUserMedia
 } from 'react-native-webrtc';
 
     if (typeof global.RTCSessionDescription === 'undefined') {
         global.RTCSessionDescription = RTCSessionDescription;
     }
+    if (typeof global.RTCIceCandidate === 'undefined') {
+        global.RTCIceCandidate = RTCIceCandidate;
+    }
 
     const navigator = global.navigator;