binary specs updated

sandbox/custom_animations/custom-animations-binary-R.json

@@ -319,8 +319,7 @@
     "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
     "meta": {
       "axes": true,
-      "description": "Plot mean is_hit of each group",
-      "custom_animation": "mean"
+      "description": "Plot mean is_hit of each group"
     },
     "data": {
       "values": [