CNAME is only set on the first simulcast layer.
It should be set on all of the layers.
Bug: webrtc:10383
Change-Id: Iea345a100769f45d09078adb93e51b7702326492
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/126541
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Amit Hilbuch <amithi@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#27134}
38e6c66f4a