A user reported to me that they are unable to create a PSBT with a legacy watchonly wallet when they use the GUI. They get an error "The amount exceeds your balance".

I think the issue is that the GUI will retrieve the wallet's balance via `AvailableCoins` before calling `CreateTransaction`. This call to `AvailableCoins` is resulting in fewer coins being returned with recent changes to how `AvailableCoins` works, particularly with additional filtering of spendable coins and preset coins.

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Note that this does not effect descriptor wallets. A workaround for this issue is to switch to using descriptor wallets. An existing legacy wallet can be turned into a descriptor wallet using the `migratewallet` RPC. However many watchonly legacy wallets are likely the result of importing descriptors via `importmulti`. For such wallets, I recommend creating a new descriptor wallet and re-importing the descriptors.
{
    // 
    // 
    pasteEntry(rv);
    return true;
}
void SendCoinsDialog::setBalance(const interfaces::WalletBalances& balances)
{
    if(model && model->getOptionsModel())
    {
        CAmount balance = balances.balance;
        if (model->wallet().hasExternalSigner()) {
            ui->labelBalanceName->setText(tr("External balance:"));
        } else if (model->wallet().isLegacy() && model->wallet().privateKeysDisabled()) {
            balance = balances.watch_only_balance;
            ui->labelBalanceName->setText(tr("Watch-only balance:"));
        }
        ui->labelBalance->setText(BitcoinUnits::formatWithUnit(model->getOptionsModel()->getDisplayUnit(), balance));
    }
}
void SendCoinsDialog::refreshBalance()
{
    setBalance(model->getCachedBalance());
    ui->customFee->setDisplayUnit(model->getOptionsModel()->getDisplayUnit());
    updateSmartFeeLabel();
}
void SendCoinsDialog::processSendCoinsReturn(const WalletModel::SendCoinsReturn &sendCoinsReturn, const QString &msgArg)