Fix UpdateIceServers method parameters format

[fedulvtubudul]

iceServerUris parameter parsing logic in UpdateIceServers method in its current state suggests that the parameter is an array of strings.

Documentation suggests that this parameter is an array of RTCIceServer structures. TS implementation uses same structure as far as I can see.

I've had part of this changes in my fork for the last year, but now I've decided to make a PR, so I added relevant test case and made parsing logic more general to support everything documentation describes.