message: Remove signature from pending collection.
diff: @@ -460,6 +460,7 @@ where
  if signatures.era_id != fs.era_id {
  warn!(public_key=%fs.public_key, "Finality signature with invalid era id.");
  // TODO: Disconnect from the sender.
  + self.remove_from_pending_fs(&*fs);
  return Effects::new();
  }
  // Populate cache so that next finality signatures don't have to read from the
  @@ -530,6 +531,7 @@ where
  .any(|sig| *sig == &fs.signature);
  // If new, gossip and store.
  if signature_known {
  + self.remove_from_pending_fs(&*fs);
  Effects::new()
  } else {
  let message = Message::FinalitySignature(fs.clone());
  @@ -544,6 +546,7 @@ where
  // manage to store it in the database.
  self.signature_cache.insert(*signature.clone());
  debug!(hash=%signature.block_hash, "storing finality signatures");
  + self.remove_from_pending_fs(&*fs);
  effects.extend(
  effect_builder
  .put_signatures_to_storage(*signature)
  