Stop logging WebRTC.Audio.AudioMixer.* histograms. Bug: chromium:1308711, chromium:1328289 Change-Id: Iba1c89a112842c532d99900cd54aee7f38f759fd Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/283680 Reviewed-by: Henrik Lundin <henrik.lundin@webrtc.org> Commit-Queue: Alessio Bazzica <alessiob@webrtc.org> Cr-Commit-Position: refs/heads/main@{#38651}