issue: cannot open streetmix url with unsupported segment variants

[kfarr]

Uncaught TypeError: Cannot read properties of undefined (reading 'length')

Error:
https://3dstreet.app/#https://streetmix.net/kfarr/129/error-proposed-owens-st

Not an error:
https://3dstreet.app/#https://streetmix.net/kfarr/130/proposed-owens-st

The issue seems to be related to drive lane variants that are not supported.

Instead, unsupported variants should be handled gracefully -- they should do best effort to render the scene

In best case there is a nice error message for user in yellow warning notification that says "Street imported from Streetmix but some segment variants are not supported." or at least a console log warning for debugging purposes

[Algorush]

I mentioned about similar issue:#464
I think it would be helpfull to have a list with supported segment types and variants also. To avoid such cases with variant support. Because now unsupported variants are much more difficult to track, since they are each processed within their own function.
I founded that already created streetmix schema for supported segments and variants when was working with text-to-street bot. I'll take it from there.
...It turned out that not all variants are in this Schema. I'm adding the rest

[kfarr]

closed by #495