fix some bugs in the notebook viewer

[andrewheumann]

BACKGROUND:

• Fixes Strange behaviour with rendering Model (in dotnet.interactive) #1083

DESCRIPTION:

• There were a couple minor bugs in the 3d viewer code which resulted in the far plane calculation being wrong, which would cause models not centered on the origin to be clipped / invisible. There were also a couple other little syntax issues.

TESTING:

• I loaded this model into a notebook and returned it in a cell. (Scratch.dib is a good place to test this out against the local version of extension.dib)
  bad-model.json

FUTURE WORK:

• We should find a way to upgrade the version of threejs in our notebook, so we can support setting DEFAULT_UP to z instead of y, but the recommended CDN approach for three these days requires importMaps, which I couldn't get to work in a notebook context.

---

This change is 

[wynged]

Reviewed 1 of 1 files at r1, all commit messages.
Reviewable status: complete! 1 of 1 approvals obtained