Tweak head syncing (#1845)

## Issue Addressed

Fixes head syncing

## Proposed Changes

- Get back to statusing peers after removing chain segments and making the peer manager deal with status according to the Sync status, preventing an old known deadlock
- Also a bug where a chain would get removed if the optimistic batch succeeds being empty

## Additional Info

Tested on Medalla and looking good

beacon_node/eth2_libp2p/src/peer_manager/mod.rs

@@ -3,6 +3,7 @@
 pub use self::peerdb::*;
 use crate::discovery::{subnet_predicate, Discovery, DiscoveryEvent, TARGET_SUBNET_PEERS};
 use crate::rpc::{GoodbyeReason, MetaData, Protocol, RPCError, RPCResponseErrorCode};
+use crate::types::SyncState;
 use crate::{error, metrics};
 use crate::{EnrExt, NetworkConfig, NetworkGlobals, PeerId, SubnetDiscovery};
 use futures::prelude::*;
@@ -844,16 +845,19 @@ impl<TSpec: EthSpec> Stream for PeerManager<TSpec> {
             }
         }
 
-        loop {
-            match self.status_peers.poll_next_unpin(cx) {
-                Poll::Ready(Some(Ok(peer_id))) => {
-                    self.status_peers.insert(peer_id.clone());
-                    self.events.push(PeerManagerEvent::Status(peer_id))
+        if !matches!(self.network_globals.sync_state(), SyncState::SyncingFinalized{..}|SyncState::SyncingHead{..})
+        {
+            loop {
+                match self.status_peers.poll_next_unpin(cx) {
+                    Poll::Ready(Some(Ok(peer_id))) => {
+                        self.status_peers.insert(peer_id.clone());
+                        self.events.push(PeerManagerEvent::Status(peer_id))
+                    }
+                    Poll::Ready(Some(Err(e))) => {
+                        error!(self.log, "Failed to check for peers to ping"; "error" => e.to_string())
+                    }
+                    Poll::Ready(None) | Poll::Pending => break,
                 }
-                Poll::Ready(Some(Err(e))) => {
-                    error!(self.log, "Failed to check for peers to ping"; "error" => e.to_string())
-                }
-                Poll::Ready(None) | Poll::Pending => break,
             }
         }