Fix instance scales

[lilleyse]

Fixes #10807

[cesium-concierge]

Thanks for the pull request @lilleyse!

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Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.

[sanjeetsuhag]

Looks good to me. Both InstancedScale and InstancedScaleNonUniform sample tilesets also have rotation so I can't test this directly, but looking at the example in the issue, I think this should suffice. Thanks @lilleyse!