NU5026 error when using UICulture

When setting a UI culture in your csproj file, a pack error occurs because NuGet.Build.Tasks.Pack.Targets is looking for files in a folder that does not exist. It is expecting files from MSBuild to be a "**en-US**" sub-folder that is not created by MSBuild.

```

en-US

```

```
Build FAILED.

[...]NuGet.Build.Tasks.Pack.targets(221,5): error NU5026: The file 'D:\MyProject\obj\Debug\net6.0-windows\en-US\MyAssembly.dll' to be packed was not found on disk.
0 Warning(s)
1 Error(s)
```

This is because the assembly was created as 'C:\MyProject\obj\Debug\net6.0-windows\MyAssembly.resources.dll' and the "en-US" sub-folder does not exist on disk.

Removing UICulture made it work again.