Issue with reference lifetimes in closures

On latest `async-trait` (0.1.77) this code doesn't compile:

```rs
struct Foo;

#[async_trait::async_trait]
trait Bar {
async fn foo(&self, call: &(dyn (Fn(&String) -> bool) + Sync));
}

#[async_trait::async_trait]
impl Bar for Foo {
async fn foo(&self, call: &(dyn (Fn(&String) -> bool) + Sync)) {
let thing = "a".to_string();
call(&thing);
}
}

fn main() {
Foo::foo(&Foo, &|a| a == "a");
}
```

This expands to:

```rs
fn foo<'life0, 'life1, 'life2, 'async_trait>(
&'life0 self,
call: &'life1 (dyn (Fn(&'life2 String) -> bool) + Sync),
) -> ::core::pin::Pin<
Box<
dyn ::core::future::Future + ::core::marker::Send + 'async_trait,
>,
>
where
'life0: 'async_trait,
'life1: 'async_trait,
'life2: 'async_trait,
Self: 'async_trait;
```

And gives the compiler error:

```
error[E0597]: `thing` does not live long enough
--> src/main.rs:12:14
|
10 | async fn foo(&self, call: &(dyn (Fn(&String) -> bool) + Sync)) {
| ---- lifetime `'1` appears in the type of `call`
11 | let thing = "a".to_string();
| ----- binding `thing` declared here
12 | call(&thing);
| -----^^^^^^-
| | |
| | borrowed value does not live long enough
| argument requires that `thing` is borrowed for `'1`
13 | }
| - `thing` dropped here while still borrowed
```

Manually removing `'life2` makes the code compile.

Start by reproducing the example in src/main.rs and inspecting the async-trait expansion shown in the issue, focusing on the generated 'life2 constraint. Done means the example compiles without manually removing that lifetime and the behavior is covered by an appropriate regression case.

Written by the indexing model from the issue text.