### Describe the issue
Because transaction malleability isn't that much of an issue lately, we've decided to let the wallet spend zero conf change. It has happened that we create a transaction just moments before a significant increase in (higher paying) transactions. Because of #9645, there is a chance that you end up with an unconfirmed chain of 24 child transactions. If you let the wallet produce a 25th child, it will return an error because the mempool won't accept it.  This is also problematic in the case we would like to cpfp the whole chain, because other nodes won't relay the transaction to the miners.

### Can you reliably reproduce the issue?
#### If so, please list the steps to reproduce below:
1. Predict an increase in transactions. (You need a crystal ball)
2. Create transaction
3. Create more transactions
4. ?
5. Profit

### Expected behaviour
Ideally it would stop if the chain is 24 transactions long, so one could try a cpfp transaction to compensate for the fees.

### Actual behaviour
It will create a transaction chain of 25 transaction, making it hard to have the whole chain confirmed in a certain time.

### What version of bitcoin-core are you using?
Official binary: 0.13.1
#include <wallet/scriptpubkeyman.h>
#include <wallet/transaction.h>
#include <wallet/walletdb.h>
#include <wallet/walletutil.h>
#include <algorithm>
#include <atomic>
#include <map>
#include <memory>
#include <optional>
#include <set>
#include <stdexcept>
#include <stdint.h>
#include <string>
#include <utility>
#include <vector>
#include <boost/signals2/signal.hpp>
using LoadWalletFn = std::function<void(std::unique_ptr<interfaces::Wallet> wallet)>;
class CScript;
enum class FeeEstimateMode;
struct FeeCalculation;
struct bilingual_str;
namespace wallet {
struct WalletContext;
void UnloadWallet(std::shared_ptr<CWallet>&& wallet);
bool AddWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet);
bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet, std::optional<bool> load_on_start, std::vector<bilingual_str>& warnings);
bool RemoveWallet(WalletContext& context, const std::shared_ptr<CWallet>& wallet, std::optional<bool> load_on_start);
std::vector<std::shared_ptr<CWallet>> GetWallets(WalletContext& context);
std::shared_ptr<CWallet> GetWallet(WalletContext& context, const std::string& name);
std::shared_ptr<CWallet> LoadWallet(WalletContext& context, const std::string& name, std::optional<bool> load_on_start, const DatabaseOptions& options, DatabaseStatus& status, bilingual_str& error, std::vector<bilingual_str>& warnings);