Update Firefox support for pc.iceConnectionState and event (#17203)
Update Firefox support for pc.iceConnectionState and event (#17203)

This was implemented in these commits/bug:
https://github.com/mozilla/gecko-dev/commit/98794b08f642c74005534b6aeea968a36dea467b
https://github.com/mozilla/gecko-dev/commit/1cfedb856586209e976a247387ab64d95880950a

https://bugzilla.mozilla.org/show_bug.cgi?id=823512 is marked mozilla24.

Firefox 24 was confirmed with the collector tests:
http://mdn-bcd-collector.appspot.com/tests/api/RTCPeerConnection
mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data