Camera flyto fix

[kalosma]

Fix for bug #9497

The camera flyTo is not properly working when using a generic ellipsoid, for example a lunar one (ellipsoid radius: 1737400).
The final cartographic camera position is the one in WGS84 ellipsoid.

The problem is visible in the following sandcastle example.
The flyTo destination position is set to
(1737500, 0, 0)
The final camera position when the flyTo finishes is
(6378237, 0, 0)

Sandcastle example:
sandcastle

[cesium-concierge]

Thanks for the pull request @kalosma!

• ✔️ Signed CLA found.
• ❔ CHANGES.md was not updated.
  • If this change updates the public API in any way, please add a bullet point to CHANGES.md.
• ❔ Unit tests were not updated.
  • Make sure you've updated tests to reflect your changes, added tests for any new code, and ran the code coverage tool.

Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.
• Works (or fails gracefully) in IE11.

[ebogo1]

Thanks @kalosma! This change looks good to me. Could you please a unit test for this in CameraFlightPathSpec.js to test that camera properties are set as expected with the new change? CHANGES.md should be updated as well to indicate the bug fix.

cc @lilleyse

[kalosma]

@ebogo1 thanks for looking into this. I added the new test and updated CHANGES.md. Please let me know if anything else is needed

[ebogo1]

I verified that these changes work in Sandcastle and that the build will pass on CesiumJS master. Just a couple small tweaks and this should be good to go!

[kalosma]

Thanks @ebogo1! All changes should be in now. Let me know if I need to change anything else

[ebogo1]

Looks good, thanks @kalosma!