Remove old proposed blocks check

[JakubFornadel]

Task Description

In case nodes do not print this err msg:

  if (const auto& err_msg = proposed_blocks_.checkOldBlocksPresence(current_pbft_period); err_msg.has_value()) {
    LOG(log_er_) << "Old proposed blocks saved in db <period> -> <blocks count>: " << *err_msg;
  }

remove the check & log

Epic Parent