Update Rust Edition to 2024 (#7766)

* #7749

Thanks @dknopik and @michaelsproul for your help!

validator_client/signing_method/src/lib.rs

@@ -6,7 +6,7 @@
 use eth2_keystore::Keystore;
 use lockfile::Lockfile;
 use parking_lot::Mutex;
-use reqwest::{header::ACCEPT, Client};
+use reqwest::{Client, header::ACCEPT};
 use std::path::PathBuf;
 use std::sync::Arc;
 use task_executor::TaskExecutor;