Call SetMaxBitrate when encoder is configured instead of in OnMaybeEncodeFrame (which is called after the initial frame dropping -> max bitrate is not set for dropped frames). Added support for single active stream configuration. Bug: none Change-Id: I33ff96e7feed70b9ea3c9b3da89f117859108347 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/231681 Reviewed-by: Sergey Silkin <ssilkin@webrtc.org> Commit-Queue: Åsa Persson <asapersson@webrtc.org> Cr-Commit-Position: refs/heads/main@{#34973}