fix (glb import) - fix special case import Blockbench glb

fix (glb import) - fix special case import Blockbench glb

The issue was the first bufview did not have a byteOffset parameter, which actually implies a byteOffset of 0.

Additionally, I noticed that the embedded gltf version of the Blockbench files uses image data URIs rather than bufview and data buffers as blender does for gltf embedded and glb. Currently this is not supported, so I think we will also need to continue using the glb converted versions of Blockbench rather than the gltf embedded files.