Never invoke rtc::LogMessage::SetLogToStderr outside of main.

rtc::LogMessage::SetLogToStderr should only be invoked by the main
function in order to enable or disable logging in a consistent way [1].

Usage of rtc::LogMessage::SetLogToStderr in other parts of the codebase
creates complex behaviors and confusion.

[1] - https://cs.chromium.org/chromium/src/third_party/webrtc/test/test_main.cc?l=88&rcl=665174fdbb4e0540eccb27cf7412348f1b65534c

Bug: None
Change-Id: Iae86fb14d7ca40af6d78d0f0cd81c5a39f65068d
Reviewed-on: https://webrtc-review.googlesource.com/91442
Reviewed-by: Erik Språng <sprang@webrtc.org>
Reviewed-by: Jonas Olsson <jonasolsson@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Reviewed-by: Steve Anton <steveanton@webrtc.org>
Commit-Queue: Steve Anton <steveanton@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24154}

api/test/video_quality_test_fixture.h

@@ -92,7 +92,6 @@ class VideoQualityTestFixtureInterface {
       bool infer_streams;
     } ss[2];
     struct Logging {
-      bool logs;
       std::string rtc_event_log_name;
       std::string rtp_dump_name;
       std::string encoded_frame_base_path;