Revert "Sanitize the codec list before sending it to the media engine"

This reverts commit add7ef974ee2642a3b55a36ec80be50a615bc60a.

Reason for revert: Cause regression in pc_full_stack_tests.cc

Original change's description:
> Sanitize the codec list before sending it to the media engine
>
> The SDP can assign the same codec to two different payload types
> which gets represented as two separate codecs in the SDP structure.
> The media engine assumes that the client does not pass down
> duplicate codecs. This change adds logic to BaseChannel to filter
> out codecs of the same name with different payload types, picking
> the one which is listed first in the m= line.
>
> Bug: chromium:987598
> Change-Id: I6fa813db1769e572ff7c3f322dc9b1de39817ea2
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/147602
> Reviewed-by: Amit Hilbuch <amithi@webrtc.org>
> Commit-Queue: Steve Anton <steveanton@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#28726}

TBR=steveanton@webrtc.org,amithi@webrtc.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: chromium:987598
Change-Id: I4ffbfcd90c81c6c6c8ee8f872f7e217d8291c857
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/147864
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Artem Titov <titovartem@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#28744}
diff --git a/pc/channel.cc b/pc/channel.cc
index 916c403..caf8c93 100644
--- a/pc/channel.cc
+++ b/pc/channel.cc
@@ -95,20 +95,6 @@
 }
 
 template <class Codec>
-std::vector<Codec> SanitizeCodecList(const std::vector<Codec>& codecs) {
-  std::vector<Codec> sanitized;
-  for (const Codec& codec : codecs) {
-    if (absl::c_any_of(sanitized, [&](const Codec& other) {
-          return codec.Matches(other);
-        })) {
-      continue;
-    }
-    sanitized.push_back(codec);
-  }
-  return sanitized;
-}
-
-template <class Codec>
 void RtpParametersFromMediaDescription(
     const MediaContentDescriptionImpl<Codec>* desc,
     const RtpHeaderExtensions& extensions,
@@ -117,7 +103,7 @@
   // a description without codecs. Currently the ORTC implementation is relying
   // on this.
   if (desc->has_codecs()) {
-    params->codecs = SanitizeCodecList(desc->codecs());
+    params->codecs = desc->codecs();
   }
   // TODO(pthatcher): See if we really need
   // rtp_header_extensions_set() and remove it if we don't.