Change all `#[allow()]` to `#[expect()]`

[DaniPopes]

expect(lint) was stabilized in 1.81.

We should use this instead of allow() so a warning is produced when the lint no longer triggers, so we can remove the entire attribute altogether.

Replace #[allow()] to #[expect()], and remove the ones that the compiler complains about.

Note that not all can be replaced, as they might be there to allow a lint that only happens on a certain configuration. In this case, they are OK.

[0xMushow]

Can I work on this please? Should this be changed accross the entire codebase?

[DaniPopes]

Yes

[grandizzy]

Closed with #10131