Remove unused APM voice activity detection sub-module

API changes:
- webrtc::AudioProcessing::Config::VoiceDetection removed
- webrtc::AudioProcessingStats::voice_detected deprecated
- cricket::AudioOptions::typing_detection deprecated
- webrtc::StatsReport::StatsValueName::
  kStatsValueNameTypingNoiseState deprecated

PSA: https://groups.google.com/g/discuss-webrtc/c/7X6uwmJarE0

Bug: webrtc:11226,webrtc:11292
Change-Id: I8d008b56708cf62961b9857ec052b59fda3b41bf
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/250666
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Gustaf Ullberg <gustaf@webrtc.org>
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Reviewed-by: Björn Terelius <terelius@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35975}

modules/audio_processing/include/audio_processing_statistics.h

@@ -24,6 +24,8 @@ struct RTC_EXPORT AudioProcessingStats {
   AudioProcessingStats(const AudioProcessingStats& other);
   ~AudioProcessingStats();
 
+  // Deprecated.
+  // TODO(bugs.webrtc.org/11226): Remove.
   // True if voice is detected in the last capture frame, after processing.
   // It is conservative in flagging audio as speech, with low likelihood of
   // incorrectly flagging a frame as voice.