message: Fix CHECK comparison for --webrtc_test_metrics_output_path on iOS.
  No-Try: True
  Fixed: b/237982523
  Cr-Commit-Position: refs/heads/main@{#38824}
diff: @@ -113,7 +113,7 @@ static absl::optional<std::vector<std::string>> g_metrics_to_plot;
  }
  }
  if (!g_webrtc_test_metrics_output_path.empty()) {
  - RTC_CHECK_NE(g_webrtc_test_metrics_output_path.find('/'), std::string::npos)
  + RTC_CHECK_EQ(g_webrtc_test_metrics_output_path.find('/'), std::string::npos)
  << "On iOS, --webrtc_test_metrics_output_path must only be a file name.";
  if ([outputDirectories count] != 0) {
  NSString *fileName = [NSString stringWithCString:g_webrtc_test_metrics_output_path.c_str()
  