Fix Rust beta compiler errors 1.78.0-beta.1 (#5439)

* remove redundant imports

* fix test

* contains key

* fmt

* Merge branch 'unstable' into fix-beta-compiler

common/eth2_interop_keypairs/src/lib.rs

@@ -23,7 +23,6 @@ use bls::{Keypair, PublicKey, SecretKey};
 use ethereum_hashing::hash;
 use num_bigint::BigUint;
 use serde::{Deserialize, Serialize};
-use std::convert::TryInto;
 use std::fs::File;
 use std::path::PathBuf;