fix gltf loader to not stop when finding uv sets >= 2
fix gltf loader to not stop when finding uv sets >= 2

sebavan/Babylon.js,sebavan/Babylon.js,BabylonJS/Babylon.js,sebavan/Babylon.js,RaananW/Babylon.js,RaananW/Babylon.js,RaananW/Babylon.js,BabylonJS/Babylon.js,BabylonJS/Babylon.js