chore: show error if texture loading failed

[zhaoyuheng200]

I'm encountering a weird scenario that fails on loading texture.
Add error output here for help debugging.

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[zhaoyuheng200]

Adding a bit more context to the PR.
I'm adding the model-explorer npm package as part of a website. the website is hosted on aws lambda.

When deployed the model-explorer in AWS Lambda with API Gateway in the front, it requires additional effort on both Lambda and APIGateway to complete a base64 encoding/decoding sequence on all binary media files.
When the encoding/decoding sequence fails, the assets http response shown on browser inspector network tab are still 200 but can't be loaded by browser ( or threejs in this instance).

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This change would help surface this issue earlier in troubleshooting efforts.