Solve struct ellipsoid caused the model to dark

[verybigzhouhai]

Solved the problem that struct ellipsoid caused the model to darken on Qualcomm platform.

[cesium-concierge]

Thank you so much for the pull request @verybigzhouhai! I noticed this is your first pull request and I wanted to say welcome to the Cesium community!

The Pull Request Guidelines is a handy reference for making sure your PR gets accepted quickly, so make sure to skim that.

• ❌ Missing CONTRIBUTORS.md entry.
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[verybigzhouhai]

@OmarShehata Hi，Now I am modifying the relevant code of the ellipsoid struct. Do you think it is acceptable?
I will continue to modify other structures if necessary.

[verybigzhouhai]

Fixes #7651

[OmarShehata]

Awesome, thanks so much for putting this together @verybigzhouhai ! I'll give this a review in the next couple of days. I'd definitely be curious if this also fixes #7871.

[verybigzhouhai]

ok,hope to pass the review

[pjcozzi]

Thanks again for contributing, @verybigzhouhai, we received your CLA.

[verybigzhouhai]

This is ready!

[verybigzhouhai]

Because of some setup reasons, I need to turn off this PR first, and I'll turn on the same one later.

[cesium-concierge]

Thanks for the awesome work @verybigzhouhai! Your contribution is about to launch to millions of users with the next release. 🚀

Do you mind if we tweet about it? CC @OmarShehata @slchow.

[OmarShehata]

Just let me know when it's ready @verybigzhouhai . Ignore the concierge message there, it's something I have to fix.