VideoCodecInitializer::SetupCodec never sets startBitrate, so SetAv1SvcConfig shouldn't use it. Bug: webrtc:12720 Change-Id: I04835dc27368f32c19132d93c72364173d7050fc Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/217382 Reviewed-by: Erik Språng <sprang@webrtc.org> Commit-Queue: Danil Chapovalov <danilchap@webrtc.org> Cr-Commit-Position: refs/heads/master@{#33915}