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

beacon_node/store/src/partial_beacon_state.rs

@@ -5,7 +5,6 @@ use crate::chunked_vector::{
 use crate::{get_key_for_col, DBColumn, Error, KeyValueStore, KeyValueStoreOp};
 use ssz::{Decode, DecodeError, Encode};
 use ssz_derive::{Decode, Encode};
-use std::convert::TryInto;
 use std::sync::Arc;
 use types::historical_summary::HistoricalSummary;
 use types::superstruct;