WMTS Time demo has lots of 400 Bad Request errors

Run https://cesiumjs.org/Cesium/Build/Apps/Sandcastle/index.html?src=Web%20Map%20Tile%20Service%20with%20Time.html&label=Showcases and open the debugger and you'll see a lot of `400 Bad Request` errors. Going to one of the bad urls directly results in:

```xml

TILEROW is out of range, maximum value is 2

```

@tfili any ideas? This happens without the new `Resource` stuff.

Open the linked Cesium Sandcastle “Web Map Tile Service with Time” demo, enable the debugger, and inspect one of the 400 Bad Request URLs. Compare the request's TILEROW value with the service's TileOutOfRange response. Done means the demo no longer produces out-of-range tile requests or repeated 400 errors.

Written by the indexing model from the issue text.