In Remoting use AudioProcessingFactory instead of AudioProcessingBuilder

AudioProcessingBuilder requires to create AudioProcessing before injecting it into peer connection factory, but when AudioProcessingFactory is injected, peer connection factory postpones construction of the same AudioProcessing until it can provide it with field trials injected into peer connection factory.
Remoting relies on default global fields trials either way, so it should be noop.

Bug: webrtc:369904700
Change-Id: I9bc3eb703c546afb00c557c38871fa25b833f1e0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5947746
Commit-Queue: Danil Chapovalov <danilchap@chromium.org>
Reviewed-by: Yuwei Huang <yuweih@chromium.org>
Reviewed-by: Tomas Gunnarsson <tommi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1375784}