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.
}
    
    m_current_transaction = std::make_unique<WalletModelTransaction>(recipients);
    WalletModel::SendCoinsReturn prepareStatus;
    updateCoinControlState();
    CCoinControl coin_control = *m_coin_control;
    coin_control.m_allow_other_inputs = !coin_control.HasSelected(); 
    prepareStatus = model->prepareTransaction(*m_current_transaction, coin_control);
    
    processSendCoinsReturn(prepareStatus,
        BitcoinUnits::formatWithUnit(model->getOptionsModel()->getDisplayUnit(), m_current_transaction->getTransactionFee()));
    if(prepareStatus.status != WalletModel::OK) {
        fNewRecipientAllowed = true;
        return false;
    }
    CAmount txFee = m_current_transaction->getTransactionFee();
    QStringList formatted;
    for (const SendCoinsRecipient &rcp : m_current_transaction->getRecipients())
    {
        
        QString amount = BitcoinUnits::formatWithUnit(model->getOptionsModel()->getDisplayUnit(), rcp.amount);
        if (model->isMultiwallet()) {
            amount.append(tr(" from wallet '%1'").arg(GUIUtil::HtmlEscape(model->getWalletName())));
        }
        
        QString address = rcp.address;
        QString recipientElement;
        {
            if(rcp.label.length() > 0) 
            {