Upload frame_request_pending_latency [attempt #2] (#135890)

These values are generated since #135279, but I didn't know to add the new keys to this list to get them to upload. 

Failed to do so in #135645, I believe the mistake there was putting them in `_kCommonScoreKeys`, which is also used in "E2E" tests, that don't get full trace data, only high level `FrameTiming` packets.

Part of #129150

dev/devicelab/lib/tasks/perf_tests.dart

@@ -1300,6 +1300,9 @@ class PerfTest {
           'average_vsync_transitions_missed',
           '90th_percentile_vsync_transitions_missed',
           '99th_percentile_vsync_transitions_missed',
+          'average_frame_request_pending_latency',
+          '90th_percentile_frame_request_pending_latency',
+          '99th_percentile_frame_request_pending_latency',
           if (measureCpuGpu && !isAndroid) ...<String>[
             // See https://github.com/flutter/flutter/issues/68888
             if (data['average_cpu_usage'] != null) 'average_cpu_usage',

dev/devicelab/test/perf_tests_test.dart

@@ -58,6 +58,9 @@ void main() {
       'average_vsync_transitions_missed': 1,
       '90th_percentile_vsync_transitions_missed': 1,
       '99th_percentile_vsync_transitions_missed': 1,
+      'average_frame_request_pending_latency': 0.1,
+      '90th_percentile_frame_request_pending_latency': 0.1,
+      '99th_percentile_frame_request_pending_latency': 0.1,
     };
     const String resultFileName = 'fake_result';
     void driveCallback(List<String> arguments) {
@@ -108,6 +111,9 @@ void main() {
       '90hz_frame_percentage': 0.4,
       '120hz_frame_percentage': 0.6,
       'illegal_refresh_rate_frame_count': 10,
+      'average_frame_request_pending_latency': 0.1,
+      '90th_percentile_frame_request_pending_latency': 0.1,
+      '99th_percentile_frame_request_pending_latency': 0.1,
     };
     const String resultFileName = 'fake_result';
     void driveCallback(List<String> arguments) {