GLTFLoader does not support fully PBR

[tgranie]

Describe the bug

• Following https://github.com/xeokit/xeokit-sdk/issues/1506, Same code
• Load the glb file attached using the code
• Load the glb file attached in https://3dviewer.net

Expected behavior

The glb should be rendered

Screenshots

xeokit with pbr enabled

3dviewer