Add a VoiceActivityDetectorWrapper submodule in AudioProcessingImpl and enable injecting speech probability into GainController2. Bug: webrtc:13663 Change-Id: I05e13b737d085b45ac8ce76660191867c56834c2 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/265166 Commit-Queue: Hanna Silen <silen@webrtc.org> Reviewed-by: Alessio Bazzica <alessiob@webrtc.org> Cr-Commit-Position: refs/heads/main@{#37275}