Restore some metrics in call_perf_tests.cc

Switch "min_test_bitrate_", "bitrate_stats_min_transmit_bitrate" and
"bitrate_stats_without_min_transmit_bitrate" from kKilobitsPerSecond
to kUnitless to avoid conversion to bytesPerSecond in the Chrome
Perf Dasboard.

Bug: b/246095034, webrtc:14479
Change-Id: Id8a4a104dd351670aec63415087d8825acaa3d48
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/277221
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38236}
diff --git a/call/call_perf_tests.cc b/call/call_perf_tests.cc
index 3b6db5d..3d8041e 100644
--- a/call/call_perf_tests.cc
+++ b/call/call_perf_tests.cc
@@ -738,7 +738,7 @@
           std::string("bitrate_stats_") +
               (pad_to_min_bitrate_ ? "min_transmit_bitrate"
                                    : "without_min_transmit_bitrate"),
-          "bitrate_kbps", bitrate_kbps_list_, Unit::kKilobitsPerSecond,
+          "bitrate_kbps", bitrate_kbps_list_, Unit::kUnitless,
           ImprovementDirection::kNeitherIsBetter);
     }
 
@@ -1017,7 +1017,7 @@
           << "Minimum supported bitrate out of the test scope";
       GetGlobalMetricsLogger()->LogSingleValueMetric(
           "min_test_bitrate_", "min_bitrate", last_passed_test_bitrate,
-          Unit::kKilobitsPerSecond, ImprovementDirection::kNeitherIsBetter);
+          Unit::kUnitless, ImprovementDirection::kNeitherIsBetter);
     }
 
     void OnCallsCreated(Call* sender_call, Call* receiver_call) override {