KML lines can only be clamped when tessellate is set to true

[OmarShehata]

In CesiumJS, loading in a KML that has lines and setting clampToGround: true will not clamp the line unless you have <tesselate>1</tesselate>. We added a warning about this here: #8428. But opening this issue because this behavior does not match what you see when loading the KML in Google Earth, and wanted to document that we should consider changing this behavior in the future.

You can test with an inline KML in this Sandcastle. Set <tessellate>0</tessellate> and the line will no longer clamp.

Here are two KML files you can also test with. Both of these are clamped in Earth, only one is clamped in CesiumJS (the one that has tesselate to true).

This originally came up here #8404 and it took me a while to figure out that tesselating was a requirement. It just came up again on the forum here.