[A17] Ancient Dangers support impossibly large roofs

[Mehni]

What happens:
Ancient dangers can generate with a size that doesn't respect the roof support boundaries, with potentially deadly consequences when players attempt to remove a load-bearing wall.

What you expected to happen.
I expect Ancient Dangers to not break the laws of physics as RimWorld knows it, vaulted ceilings be damned.

Repro steps:
Generate a couple of ancient dangers, observe size.

[ison]

Fixed for A18, thanks.