android: fix accessing the iceServers attribute

Fixes:
react-native-webrtc#921

Author: saghul

android/src/main/java/com/oney/WebRTCModule/WebRTCModule.java

@@ -188,7 +188,7 @@ private List<PeerConnection.IceServer> createIceServers(ReadableArray iceServers
 
     private PeerConnection.RTCConfiguration parseRTCConfiguration(ReadableMap map) {
         ReadableArray iceServersArray = null;
-        if (map != null) {
+        if (map != null && map.hasKey("iceServers")) {
             iceServersArray = map.getArray("iceServers");
         }
         List<PeerConnection.IceServer> iceServers = createIceServers(iceServersArray);
@@ -198,8 +198,7 @@ private PeerConnection.RTCConfiguration parseRTCConfiguration(ReadableMap map) {
         }
 
         // iceTransportPolicy (public api)
-        if (map.hasKey("iceTransportPolicy")
-                && map.getType("iceTransportPolicy") == ReadableType.String) {
+        if (map.hasKey("iceTransportPolicy") && map.getType("iceTransportPolicy") == ReadableType.String) {
             final String v = map.getString("iceTransportPolicy");
             if (v != null) {
                 switch (v) {