See-through tiles don't exist on TG

[JohnFulpWillard]

**Issue Description: **

Turfs that lets you see the floor below appear as invisible in Webmap, biggest example is glass floors

Icebox - https://webmap.affectedarc07.co.uk/maps/tgstation/icebox/

Deltastation - https://webmap.affectedarc07.co.uk/maps/tgstation/deltastation/

Metastation in-game vs webmap

They don't need to display the floor below (Icebox is the only of the 3 examples that's multi-z at all), but at least showing that there's a floor there would be nice

Monkestation's Deltastation works, in comparison - https://webmap.affectedarc07.co.uk/maps/monkestation/deltastation/

**Affected Pages: **

https://webmap.affectedarc07.co.uk/maps/tgstation/icebox/
https://webmap.affectedarc07.co.uk/maps/tgstation/deltastation/
https://webmap.affectedarc07.co.uk/maps/tgstation/metastation/

**Steps to reproduce: **

Visit any of the pages linked

[AffectedArc07]

Might need an sdmm update, will check