Change sandbox to play only the first glTF animation

sandbox/index.js

@@ -38,7 +38,6 @@ if (BABYLON.Engine.isSupported()) {
         currentPluginName = plugin.name;
 
         if (plugin.name === "gltf" && plugin instanceof BABYLON.GLTFFileLoader) {
-            plugin.animationStartMode = BABYLON.GLTFLoaderAnimationStartMode.ALL;
             plugin.compileMaterials = true;
         }
     });