stats: don't rely on candidate stats "ip" or "deleted" members

[fippo]

For forward-compability please stop relying on (at least)

• candidate stats ip which got replaced by address (and may not be present in some browsers for fingerprinting reasons)
• [candidate stats] deleted](https://github.com/twilio/twilio-video.js/blob/master/lib/webrtc/getstats.js#L121) which is already gone
  in https://github.com/twilio/twilio-video.js/blob/master/lib/webrtc/getstats.js

I have no intent to remove ip at this time but that is rather because there is no way to know how much would break as a result.

[manjeshbhargav]

@fippo ,

Thanks for the tip. Regarding ip, is there any timeline on when this will be deprecated and removed? As for deleted, although we do look for it, we have alternative code paths for handling its absence. So, in my view, we will focus on ip based on Chrome's timeline for deprecation and removal.