Refresh sample10 metric JSON exports to null

artifacts/results/metric_iter31_sample10_all_metrics_verify/episode14/episode14.metrics.json

@@ -11,10 +11,10 @@
   "retrieve_cross_frame": -1,
   "ready_cross_frame": 228,
   "ordering_ok": true,
-  "dense_boundary_error_to_retrieve_frames": NaN,
+  "dense_boundary_error_to_retrieve_frames": null,
   "dense_boundary_error_frames": 49.0,
   "dense_boundary_error_fraction": 0.14984709480122324,
-  "key_boundary_error_to_retrieve_keyframes": NaN,
+  "key_boundary_error_to_retrieve_keyframes": null,
   "key_boundary_error_keyframes": 0.0,
   "auroc_vret_ypre_three": 0.9740308370044053,
   "auprc_vret_ypre_three": 0.9483243162169741,
@@ -24,9 +24,9 @@
   "auprc_ppre_ypre": 0.9803921568627451,
   "auroc_pext_yext": 1.0,
   "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": 0.993421052631579,
   "auprc_phase_yready": 0.9705882352941176,
   "f1_phase_yready": 0.8016194331983807,