No error reported to the user when quantized-mesh / layer.json tiles fail to load

[kring]

I saw this in Cesium for Unity, but it's most likely a cesium-native problem, not specific to Unity.

If a particular tile from a tileset.json is missing, users will see a message in the log:

[2024-11-04 18:13:29.274] [error] [TilesetJsonLoader.cpp:924] Received status code 404 for tile content http://localhost:8080/batchedColors.b3dm

However, if one of the .terrain files in quantized-mesh / layer.json is missing, the error is silently ignored, leaving users wondering why there's a hole in their terrain.

Originally reported by a user here:
https://community.cesium.com/t/tile-not-rendering-which-closer-to-camera/36033