Merge pull request #12941 from CesiumGS/remove-defaultvalue

Remove defaultValue and defaultValue.EMPTY_OBJECT

Author: jjspace

CHANGES.md

@@ -8,6 +8,8 @@
 
 #### Breaking Changes :mega:
 
+- The `defaultValue` function has been removed. Instead, use the [nullish coalescing (`??`)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Nullish_coalescing) operator. See the [Coding Guide](https://github.com/CesiumGS/cesium/tree/main/Documentation/Contributors/CodingGuide#default-parameter-values) for usage information and examples.
+- `defaultValue.EMPTY_OBJECT` has been removed. Instead, use `Frozen.EMPTY_OBJECT`. See the [Coding Guide](https://github.com/CesiumGS/cesium/tree/main/Documentation/Contributors/CodingGuide#default-parameter-values) for usage information and examples.
 - Voxel rendering now requires a WebGL2 context, which is [enabled by default since 1.101](https://github.com/CesiumGS/cesium/pull/10894). For voxel rendering, make sure the `requestWebGl1` flag in `contextOptions` is NOT set to true.
 
 #### Fixes :wrench: