`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_unittest.cc b/modules/audio_processing/audio_processing_unittest.cc
index 5af8aa9..e763b78 100644
--- a/modules/audio_processing/audio_processing_unittest.cc
+++ b/modules/audio_processing/audio_processing_unittest.cc
@@ -2673,14 +2673,13 @@
 
 TEST(ApmConfiguration, EchoControlInjection) {
   // Verify that apm uses an injected echo controller if one is provided.
-  webrtc::Config webrtc_config;
   std::unique_ptr<EchoControlFactory> echo_control_factory(
       new MyEchoControlFactory());
 
   rtc::scoped_refptr<AudioProcessing> apm =
       AudioProcessingBuilderForTesting()
           .SetEchoControlFactory(std::move(echo_control_factory))
-          .Create(webrtc_config);
+          .Create();
 
   Int16FrameData audio;
   audio.num_channels = 1;
@@ -2700,9 +2699,8 @@
 }
 
 rtc::scoped_refptr<AudioProcessing> CreateApm(bool mobile_aec) {
-  Config old_config;
   rtc::scoped_refptr<AudioProcessing> apm =
-      AudioProcessingBuilderForTesting().Create(old_config);
+      AudioProcessingBuilderForTesting().Create();
   if (!apm) {
     return apm;
   }