glTF-Embedded format cannot be viewed in the Web Viewer

**Describe the bug**
The following `glTF-Embedded` format model cannot be displayed in the [Web Viewer](https://google.github.io/filament/viewer/).
https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Box/glTF-Embedded

**To Reproduce**
1. Download the model below.
https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Box/glTF-Embedded

2. Try to view the above model in Filament Web Viewer.
https://google.github.io/filament/viewer/

**Expected behavior**
I expected the red cube to be visible in the viewer.

**Screenshots**
The screen does not change.

**Logs**
No error is displayed on the console.

**Desktop (please complete the following information):**
- OS: Windows 10
- Browser : Chrome 92
- GPU: NVIDIA GeForce RTX 2060
- Backend: WebGL + ANGLE

**Additional context**
It seems that there is a problem in handling the `glTF-Embedded` format. The models in the following formats were displayed without problems.

https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Box/glTF
https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Box/glTF-Binary
https://github.com/KhronosGroup/glTF-Sample-Models/tree/master/2.0/Box/glTF-Draco