Treat LOD3 like it's completely disabled if the lod_3 folder is not found in the brick library directory.

[cdmpants]

We should treat LOD3 like it's disabled in import settings if a lod_3 folder can't be found in the user-set brick library directory. Right now, if a user is using their vanilla LU client for bricks, and they have LOD3 enabled in import settings, then LOD_3 will import as empties and will factor into dynamic LOD. This result not desirable.