Type inference bug with self-application of a generic function containing `ParamSpec`

**Describe the bug**
In the following example, pyright doesn't correctly "freshen" the ParamSpec `P` resulting in a partially unknown type.

**Code or Screenshots**

```python
from collections.abc import Callable

def id[**P, R](c: Callable[P, R]) -> Callable[P, R]: ...

reveal_type(id(id))
# (c: (...) -> Unknown) -> ((**P(1)@id) -> R(1)@id)
```

Start by running the provided generic-function self-application example and inspecting the type-inference handling for ParamSpec freshening. Confirm the current reveal_type output, then verify that self-application no longer leaves a partially unknown type.

Written by the indexing model from the issue text.