Fix: null-ref in networkPeer (#937)

* Fixes nullref in networkPeer

* Removes inflight semaphore

* Revert "Removes inflight semaphore"

This reverts commit 26ec15c6f7.

codex/blockexchange/network/network.nim

@@ -93,18 +93,20 @@ proc send*(b: BlockExcNetwork, id: PeerId, msg: pb.Message) {.async.} =
   ## Send message to peer
   ##
 
-  b.peers.withValue(id, peer):
+  if not (id in b.peers):
+    trace "Unable to send, peer not found", peerId = id
+    return
+
+  let peer = b.peers[id]
   try:
     await b.inflightSema.acquire()
-      await peer[].send(msg)
+    await peer.send(msg)
   except CancelledError as error:
     raise error
   except CatchableError as err:
     error "Error sending message", peer = id, msg = err.msg
   finally:
     b.inflightSema.release()
-  do:
-    trace "Unable to send, peer not found", peerId = id
 
 proc handleWantList(
   b: BlockExcNetwork,