message: Make sure next_block_height is kept up to date
diff: //! Most importantly, it doesn't care about what messages it's forwarding.
  // TODO:
  -// - next_block_height / next_executed_height?
  // - drop all eras when reverting to CatchUp mode? (Or don't!? Highway won't remember state.)
  // - check for 1 deploy TTL worth of complete blocks for the replay protection (should it live in
  // the storage/linear chain/era_supervisor/other?)
  @@ -308,6 +307,7 @@ impl EraSupervisor {
  #[allow(clippy::integer_arithmetic)] // Block height should never reach u64::MAX.
  fn executed_block(&mut self, block_header: &BlockHeader) {
  self.next_executed_height = self.next_executed_height.max(block_header.height() + 1);
  + self.next_block_height = self.next_block_height.max(self.next_executed_height);
  self.update_consensus_pause();
  }
  