`ExperimentalNs` removed + APM not depending anymore on `webrtc::Config`

Thanks to the elimination of `ExperimentalNs`, there is no need anymore
to pass `webrtc::Config` to build APM.
Hence, `AudioProcessingBuilder::Create(const webrtc::Config&)` is also
removed.

Bug: webrtc:5298
Change-Id: I0a3482376a7753434486fe564681f7b9f83939c5
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/232128
Reviewed-by: Sam Zackrisson <saza@webrtc.org>
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35025}
diff --git a/modules/audio_processing/audio_processing_impl.h b/modules/audio_processing/audio_processing_impl.h
index 27abbd4..7c54173 100644
--- a/modules/audio_processing/audio_processing_impl.h
+++ b/modules/audio_processing/audio_processing_impl.h
@@ -55,10 +55,9 @@
  public:
   // Methods forcing APM to run in a single-threaded manner.
   // Acquires both the render and capture locks.
-  explicit AudioProcessingImpl(const webrtc::Config& config);
+  AudioProcessingImpl();
   // AudioProcessingImpl takes ownership of capture post processor.
-  AudioProcessingImpl(const webrtc::Config& config,
-                      std::unique_ptr<CustomProcessing> capture_post_processor,
+  AudioProcessingImpl(std::unique_ptr<CustomProcessing> capture_post_processor,
                       std::unique_ptr<CustomProcessing> render_pre_processor,
                       std::unique_ptr<EchoControlFactory> echo_control_factory,
                       rtc::scoped_refptr<EchoDetector> echo_detector,