Add backwards compatibilty to peer codecs config.

This is a small follow-up to
https://webrtc-review.googlesource.com/c/src/+/226220 in order to make
the switch incremental.

No-Try: True
Bug: b/192821182
Change-Id: I2e36c74eb97b5ee30cbd5c383eebff73e9389408
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/226221
Commit-Queue: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Andrey Logvin <landrey@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34478}
diff --git a/test/pc/e2e/peer_configurer.cc b/test/pc/e2e/peer_configurer.cc
index caf29eb..50ce51b 100644
--- a/test/pc/e2e/peer_configurer.cc
+++ b/test/pc/e2e/peer_configurer.cc
@@ -100,6 +100,9 @@
         p->video_codecs.push_back(
             PeerConnectionE2EQualityTestFixture::VideoCodecConfig(
                 cricket::kVp8CodecName));
+        run_params->video_codecs = {
+            PeerConnectionE2EQualityTestFixture::VideoCodecConfig(
+                cricket::kVp8CodecName)};
       }
     } else {
       RTC_CHECK(run_params->video_codecs.empty())