Beta compiler fixes (#5543)

* remove duplicate imports in gossip tests. get rid of duplicate trait bound locations

* more double import fixes

* cargo fmt

beacon_node/lighthouse_network/gossipsub/src/protocol.rs

@@ -508,7 +508,6 @@ impl Decoder for GossipsubCodec {
 mod tests {
     use super::*;
     use crate::config::Config;
-    use crate::protocol::{BytesMut, GossipsubCodec, HandlerEvent};
     use crate::{Behaviour, ConfigBuilder, MessageAuthenticity};
     use crate::{IdentTopic as Topic, Version};
     use libp2p::identity::Keypair;