PSA: RTP header id collisions are rejected during setRemoteDescription in M116+

[Philipp Hancke]

prior to

  https://chromiumdash.appspot.com/commit/4bf52387e78e0a88c806c7e2c3646756f80e4515

which landed in M116 setRemoteDescription accepted SDP which contained different RTP header extensions with the same extension id as part of a single BUNDLE group.

This isn't allowed as it is not possible to tell what the extension means and now throws an error.

Measurements have shown this to be very rare but please test in Canary and Beta and update your code accordingly.

cheers

Philipp