Added GetMaterialAtPosition to MeshTerrainRoot, hooked up to evaluate when a position is in the deep sea This solves footstep sounds and impact fx on the deep sea islands not working as expected Had to emulate the SetupSplatLookup process from TerrainSplatMap This will be skipped on the server as MeshTerrainRoot is an IClientComponent, which I believe should be fine since we largely use this for fx S2P all islands