Also cleans up the unused parameters from GetSimulcastConfig. Bug: webrtc:8785, webrtc:8486 Change-Id: I1aea8f6c9e6590211ec5ee5cafc0ec2a2100d68f Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/144627 Reviewed-by: Rasmus Brandt <brandtr@webrtc.org> Reviewed-by: Erik Språng <sprang@webrtc.org> Reviewed-by: Sergey Silkin <ssilkin@webrtc.org> Commit-Queue: Florent Castelli <orphis@webrtc.org> Cr-Commit-Position: refs/heads/master@{#28496}