message: rpc: swap position of banned_until and ban_created fields
  A ban expires after its creation. Therefore, for the listbanned RPC,
  position banned_until after ban_created in help and output.
diff: @@ -750,8 +750,8 @@ static RPCHelpMan listbanned()
  {RPCResult::Type::OBJ, "", "",
  {
  {RPCResult::Type::STR, "address", ""},
  - {RPCResult::Type::NUM_TIME, "banned_until", ""},
  {RPCResult::Type::NUM_TIME, "ban_created", ""},
  + {RPCResult::Type::NUM_TIME, "banned_until", ""},
  }},
  }},
  RPCExamples{
  @@ -774,8 +774,8 @@ static RPCHelpMan listbanned()
  const CBanEntry& banEntry = entry.second;
  UniValue rec(UniValue::VOBJ);
  rec.pushKV("address", entry.first.ToString());
  - rec.pushKV("banned_until", banEntry.nBanUntil);
  rec.pushKV("ban_created", banEntry.nCreateTime);
  + rec.pushKV("banned_until", banEntry.nBanUntil);
  bannedAddresses.push_back(rec);
  }
  