fix(iroh-net): Fix a compiler error with newer derive_more versions (…

…#2578)

## Description

<!-- A summary of what this pull request achieves and a rough list of
changes. -->
The `#[derive(Debug)]` used to generate an impl like this:
```rust
#[automatically_derived]
impl<'a> ::core::fmt::Debug for Accept<'a>
where
    quinn::Accept<'a>: ::core::fmt::Debug,
    Endpoint: ::core::fmt::Debug,
{
// ...
}
```

But `quinn::Accept` doesn't implement `Debug`.

## Breaking Changes

<!-- Optional, if there are any breaking changes document them,
including how to migrate older code. -->
None

## Notes & open questions

<!-- Any notes, remarks or open questions you have to make about the PR.
-->
I'm... Really stumped on what changed in `derive_more`. When I expand
the macro, in both versions there's a `Debug` bound on `quinn::Accept`,
which just can't be right... Anyhow.

## Change checklist

- [X] Self-review.
- ~~[ ] Documentation updates following the [style
guide](https://rust-lang.github.io/rfcs/1574-more-api-documentation-conventions.html#appendix-a-full-conventions-text),
if relevant.~~
- ~~[ ] Tests if relevant.~~
- [X] All breaking changes documented.