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.
{
    unsubscribeFromCoreSignals();
}
void WalletModel::startPollBalance()
{
    
    
    pollBalanceChanged();
    
    
    
    connect(timer, &QTimer::timeout, this, &WalletModel::timerTimeout);
    GUIUtil::ExceptionSafeConnect(this, &WalletModel::timerTimeout, this, &WalletModel::pollBalanceChanged);
    timer->start(MODEL_UPDATE_DELAY);
}
void WalletModel::setClientModel(ClientModel* client_model)
{
    m_client_model = client_model;
    if (!m_client_model) timer->stop();
}
void WalletModel::updateStatus()