fix: sugar house outdoor terrain

[0Monet]

Purpose of change

Replace the outdoor sugar house terrain with something better.
Remove "weight".

Describe the solution

Use "t_region_groundcover" and delete unnecessary "set" lines.

Describe alternatives you've considered

Do nothing.

Testing

1. Changes didn't crash my game.

Additional context

Before:

After:

[chaosvolt]

Weight is probably still okay to have on the off chance that someone adds a variant in a mod, but eh it has a default of I think 1000 in the hardcode so not that big an issue. :>