Refresh sample10 metric JSON exports to null

artifacts/results/metric_iter31_sample10_all_metrics_verify/episode90/episode90.metrics.json

@@ -11,10 +11,10 @@
   "retrieve_cross_frame": -1,
   "ready_cross_frame": 248,
   "ordering_ok": true,
-  "dense_boundary_error_to_retrieve_frames": NaN,
+  "dense_boundary_error_to_retrieve_frames": null,
   "dense_boundary_error_frames": 95.0,
   "dense_boundary_error_fraction": 0.2852852852852853,
-  "key_boundary_error_to_retrieve_keyframes": NaN,
+  "key_boundary_error_to_retrieve_keyframes": null,
   "key_boundary_error_keyframes": 3.0,
   "auroc_vret_ypre_three": 0.9578849721706865,
   "auprc_vret_ypre_three": 0.9001943636691713,
@@ -24,9 +24,9 @@
   "auprc_ppre_ypre": 1.0,
   "auroc_pext_yext": 0.9999999999999999,
   "auprc_pext_yext": 1.0,
-  "auroc_phase_yretrieve": NaN,
-  "auprc_phase_yretrieve": NaN,
-  "f1_phase_yretrieve": NaN,
+  "auroc_phase_yretrieve": null,
+  "auprc_phase_yretrieve": null,
+  "f1_phase_yretrieve": null,
   "auroc_phase_yready": 0.9939516129032258,
   "auprc_phase_yready": 0.9659090909090909,
   "f1_phase_yready": 0.6415094339622641,