Using delegates on a method breaks TypeDispatch

Adding a `delegates` decorator to a method prevents `TypeDispatch` from creating the correct dispatching table.

Without `delegates`, the dispatch for `TensorAudio.create` is correct:

```python
class TensorAudio(TensorBase):
@classmethod
def create(cls, fn:str|Path, **kwargs):
sig, sr = torchaudio.load(fn, **kwargs)
return cls(sig, sr=sr)
```
`TypeDispatch(TensorAudio.create)` returns
```text
(str,object) -> create
(Path,object) -> create
```

But with delegates, `TypeDispatch` doesn't create the correct dispatch table:

```python
class TensorAudio(TensorBase):
@delegates(torchaudio.load)
@classmethod
def create(cls, fn:str|Path, **kwargs):
sig, sr = torchaudio.load(fn, **kwargs)
return cls(sig, sr=sr)

TypeDispatch(TensorAudio.create)
```
Instead `TypeDispatch(TensorAudio.create)` returns:
```text
(str,BinaryIO) -> create
(str,str) -> create
(str,PathLike) -> create
(Path,BinaryIO) -> create
(Path,str) -> create
(Path,PathLike) -> create
```
The `BinaryIO`, `str`, and `PathLike` in the type dispatch are from `torchaudio.load`. It's missing `(str,object)` and `(Path,object)`. This incorrect dispatch prevents from `TensorAudio.create` dispatching in a fastai datablock.

Previous versions of fastcore did not have this interplay between `delegates` and `TypeDispatch`, but I am not sure when it cropped up.

Reproduce the issue with the TensorAudio.create examples and inspect the interaction between the delegates decorator and TypeDispatch. Compare the generated dispatch tables with and without delegates, then verify that the table retains the (str,object) and (Path,object) entries and allows TensorAudio.create to dispatch in a fastai datablock.

Written by the indexing model from the issue text.