Add passing optional speech level and speech probability to Process(). This enables computing an override for the RMS error from Agc::GetRmsErrorDb(). Currently no speech level or probability are passed outside the tests and no override happens elsewhere. Bug: webrtc:7494 Change-Id: I0a7b1204aa51bcde8588963a5af023410405e83d Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/277560 Reviewed-by: Alessio Bazzica <alessiob@webrtc.org> Commit-Queue: Hanna Silen <silen@webrtc.org> Cr-Commit-Position: refs/heads/main@{#38318}