Remove legacy implementation of AudioEncoderFactory::MakeAudioEncoder in a pc test

All calls in code under test were migrated to AudioEncoderFactory::Create and thus there is no longer need to propagate older function.

Bug: webrtc:343086059
Change-Id: I9e0ea4024759deb22c0d284e0e4bac7322a08f62
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/357181
Commit-Queue: Danil Chapovalov <danilchap@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#42638}
diff --git a/pc/peer_connection_end_to_end_unittest.cc b/pc/peer_connection_end_to_end_unittest.cc
index 516a01e..3edfb1b 100644
--- a/pc/peer_connection_end_to_end_unittest.cc
+++ b/pc/peer_connection_end_to_end_unittest.cc
@@ -420,14 +420,6 @@
         const webrtc::SdpAudioFormat& format) override {
       return fact_->QueryAudioEncoder(format);
     }
-    std::unique_ptr<webrtc::AudioEncoder> MakeAudioEncoder(
-        int payload_type,
-        const webrtc::SdpAudioFormat& format,
-        absl::optional<webrtc::AudioCodecPairId> codec_pair_id) override {
-      EXPECT_TRUE(codec_pair_id.has_value());
-      codec_ids_->push_back(*codec_pair_id);
-      return fact_->MakeAudioEncoder(payload_type, format, codec_pair_id);
-    }
     std::unique_ptr<webrtc::AudioEncoder> Create(
         const Environment& env,
         const webrtc::SdpAudioFormat& format,