Build fails on Unreal 5.4 using Cesium For Unreal 2.8.0

[KieranCoppins]

Hi there,

I am currently getting the following build error:
Plugins\CesiumForUnreal\Source\CesiumRuntime\Private\UnrealAssetAccessors.cpp(154): error C4668: 'ENGINE_VERSION_5_4_OR_HIGHER' is not defined as a preprocessor macro, replacing with '0' for '#if/#elif'

System information:

• Unreal Engine 5.4.4
• Cesium for Unreal 2.8.0
• Visual Studio 2022 14.38.33139 toolchain
• Windows 10.0.19041.0 SDK

I believe its because UnrealAssetAccessor doesn't include CesiumCommon.h which is where the preprocessor is defined.

I will make a PR now to resolve this issue!