Add total_ui_gc_time to benchmarks captured (#96125)

diff --git a/dev/devicelab/lib/tasks/gallery.dart b/dev/devicelab/lib/tasks/gallery.dart
index fa5a69a..730f412 100644
--- a/dev/devicelab/lib/tasks/gallery.dart
+++ b/dev/devicelab/lib/tasks/gallery.dart
@@ -160,6 +160,7 @@
         '90th_percentile_picture_cache_memory',
         '99th_percentile_picture_cache_memory',
         'worst_picture_cache_memory',
+        'total_ui_gc_time',
         if (measureCpuGpu && !isAndroid) ...<String>[
           // See https://github.com/flutter/flutter/issues/68888
           if (summary['average_cpu_usage'] != null) 'average_cpu_usage',
diff --git a/dev/devicelab/lib/tasks/perf_tests.dart b/dev/devicelab/lib/tasks/perf_tests.dart
index 79ce804..d6fd87e 100644
--- a/dev/devicelab/lib/tasks/perf_tests.dart
+++ b/dev/devicelab/lib/tasks/perf_tests.dart
@@ -942,6 +942,7 @@
   'worst_picture_cache_memory',
   'new_gen_gc_count',
   'old_gen_gc_count',
+  'total_ui_gc_time',
 ];
 
 class PerfTestWithSkSL extends PerfTest {