Fix dynamic partial ellipsoids

[hpinkos]

Fixes #8271

This was an oversight on my part when I merged the partial ellipsoid PR. We need to rebuild the ellipsoid geometry when the clock and cone values change for dynamic ellipsoids.

var viewer = new Cesium.Viewer('cesiumContainer', {
    shouldAnimate: true
});

var entity = viewer.entities.add({
    position: Cesium.Cartesian3.fromDegrees(-120.0, 40.0),
    ellipsoid : {
        radii : new Cesium.CallbackProperty(setRadii, false),
        maximumCone :new Cesium.CallbackProperty(setAngle, false),
        material : Cesium.Color.BLUE.withAlpha(0.3),
        outline : true
    }
});

function setRadii(time) {
    var radius = Math.abs(Math.cos(time.secondsOfDay)) * 100000 + 30000.0;
    return new Cesium.Cartesian3(radius, radius, radius);
}

function setAngle(time) {
    var angle = Math.abs(Math.sin(time.secondsOfDay)) * Math.PI;
    return angle;
}

viewer.zoomTo(viewer.entities);

[cesium-concierge]

Thanks for the pull request @hpinkos!

• ✔️ 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.

[OmarShehata]

Thanks @hpinkos, this works well! There's just some whitespace issues. Feel free to merge after fixing that.

[hpinkos]

@OmarShehata ready