[TSP] Literal Union is not translated into a Union

### Describe the Bug

This code here:

```python
e: Literal["Hello", "There"]
```

The type of e in a TSP response is just a class with no literal value.

Pyright turns it into a TypeKind.Union with two sub types for the different literal values.

### Sandbox Link

_No response_

### (Only applicable for extension issues) IDE Information

_No response_