[Experimental] Lush Caves can generate as empty lands on the surface

The lush caves can generate on the surface as empty lands if it generates on the surface. I think lush caves are supposed to just generate underground here, not in the open. This also causes ocean features like shipwrecks and ruins to generate on the surface.

Step to Reproduce
1. Generate a new world, pick the Winding River from the seed picker.
2. Go to -2500, 1100.

Expected Result
The land doesn't generate since lush caves are only able to generate underground.

Observed Result
Somehow, the lush caves biome can generate lands on the surface in the middle of the ocean.