Hooked up the control of the adaptive AGC2 mode in audioproc_f

This CL adds the ability to toggle the AGC2 adaptive digital mode in
audioproc_f

Bug: webrtc:5298
Change-Id: If1567d8c87f88992dff89253edb293a56cee0a73
Reviewed-on: https://webrtc-review.googlesource.com/c/103361
Reviewed-by: Alex Loiko <aleloi@webrtc.org>
Commit-Queue: Per Åhgren <peah@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24954}

modules/audio_processing/test/audio_processing_simulator.h

@@ -73,6 +73,7 @@ struct SimulationSettings {
   absl::optional<int> agc_target_level;
   absl::optional<bool> use_agc_limiter;
   absl::optional<int> agc_compression_gain;
+  absl::optional<bool> agc2_use_adaptive_gain;
   float agc2_fixed_gain_db;
   float pre_amplifier_gain_factor;
   absl::optional<int> vad_likelihood;