.NET Workflows - Declarative `Question` only supports "prebuilt" entities.

Add support for complex entities such as:

- Embedded
- Closed List
'
Example:

```yaml
- kind: Question
variable: Local.Var5886
id: action-1760649787072
prompt: Please select a color
entity:
kind: EmbeddedEntity
definition:
kind: ClosedListEntity
items:
- id: option-1
displayName: red
- id: option-2
displayName: yello
displayName: Multiple choice
alwaysPrompt: false
```

Start by locating the .NET workflow handling for declarative Question entities and trace how prebuilt entities are processed. Compare that path with the EmbeddedEntity and ClosedListEntity YAML example; done means the example is accepted and its multiple-choice options work as intended.

Written by the indexing model from the issue text.