model viewer crashing on IOS

### Description

GLBs don't seem to be loading anymore on IOS. This was never an issue until yesterday/today.
Chrome does still sometimes load the model, but not always. Safari never.

Sometimes it quickly shows a light blue screen, but then it seems like it crashes.

dev tools through Safari show the below:

```
[Error] WebGL: context lost.
getContext
Tt (model-viewer.min.js:17:427081)
io (model-viewer.min.js:17:427511)
Bf (model-viewer.min.js:798:756)
singleton (model-viewer.min.js:798:1454)
h (model-viewer.min.js:1092:27764)
d (model-viewer.min.js:1092:20040)
y (model-viewer.min.js:1092:8716)
s (model-viewer.min.js:1092:6639)
s (model-viewer.min.js:1092:5398)
s (model-viewer.min.js:1092:2787)
r (model-viewer.min.js:1092:480)
define
Module Code (model-viewer.min.js:1092:31837)
[Warning] TypeError: null is not an object (evaluating 't.getShaderPrecisionFormat(t.VERTEX_SHADER,t.HIGH_FLOAT).precision') — model-viewer.js:15391 (model-viewer.min.js, line 798)
[Error] TypeError: undefined is not an object (evaluating 'this.threeRenderer.xr')
Hg (model-viewer.min.js:728:2069)
Bf (model-viewer.min.js:798:1084)
singleton (model-viewer.min.js:798:1454)
h (model-viewer.min.js:1092:27764)
d (model-viewer.min.js:1092:20040)
y (model-viewer.min.js:1092:8716)
s (model-viewer.min.js:1092:6639)
s (model-viewer.min.js:1092:5398)
s (model-viewer.min.js:1092:2787)
r (model-viewer.min.js:1092:480)
define
Module Code (model-viewer.min.js:1092:31837)
[Error] Unhandled Promise Rejection: TypeError: undefined is not an object (evaluating 'e.getFieldOfView')
(anonymous function) (model-viewer.min.js:1092:16774)
(anonymous function) (model-viewer.min.js:1092:16976)
(anonymous function) (model-viewer.min.js:1011:5994)
(anonymous function) (model-viewer.min.js:1011:2413)
[Log] THREE.WebGLRenderer: Context Lost. (model-viewer.min.js, line 17)
```

#### Live Demo
https://a.rendered.ar/api/EmbedTrigger?uuid=8348-G&rda=123456

### Version
- model-viewer: v3.5.0

### Browser Affected
- [ ] Chrome IOS
- [ ] Safari IOS

### OS
- [ ] iOS