[Bug]: vscode: invalid const assignment causes type hints to fail

### Describe the bug

If the declared type and the assigned type of a const are misaligned, then when the const is used elsewhere, the type hint says "(error)" instead of showing the declared type:


I would expect to see "const foobad1: { Bar : string }".

### Reproduction

Drop this into VSCode and mouse over `foobad1`:

```
const foobad1 : {Bar : string} = #{Bar: 7};

@example(foobad1)
model Foo { Bar : string; }
```

### Checklist

- [X] Follow our [Code of Conduct](https://github.com/microsoft/typespec/blob/main/CODE_OF_CONDUCT.md)
- [X] Check that there isn't already an issue that request the same bug to avoid creating a duplicate.
- [X] Check that this is a concrete bug. For Q&A open a [GitHub Discussion](https://github.com/Microsoft/typespec/discussions).
- [X] The provided reproduction is a [minimal reproducible example](https://stackoverflow.com/help/minimal-reproducible-example) of the bug.