Error when HDR is turned off, log depth is disabled, and shadows are enabled

In this [sandcastle](https://sandcastle.cesium.com/#c=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) uncheck HDR and you get an error

```
TypeError: Cannot read property 'execute' of undefined
at executeCommand (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:239389:64)
at executeCommands (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:239756:21)
at executeCommandsInViewport (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:240177:13)
at Scene.updateAndExecuteCommands (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:239970:17)
at render (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:240633:19)
at tryAndCatchError (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:240652:17)
at Scene.render (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:240727:17)
at CesiumWidget.render (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:253442:29)
at render (https://sandcastle.cesium.com/CesiumUnminified/Cesium.js:252779:36)
```

The error does not happen if HDR is disabled initially, or even when HDR is disabled initially, then enabled, then disabled. The error is related to derived commands and has existed as far back as HDR was introduced in 1.52.

Reproduce the failure in the linked Sandcastle example by toggling HDR off with log depth disabled and shadows enabled. Start from the executeCommand and derived-command paths shown in the Cesium.js stack trace, then verify that the same setting changes no longer throw an error; the issue provides no source file or test path.

Written by the indexing model from the issue text.