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.
{
    EncryptionStatus newEncryptionStatus = getEncryptionStatus();
    if(cachedEncryptionStatus != newEncryptionStatus) {
        Q_EMIT encryptionStatusChanged();
    }
}
void WalletModel::pollBalanceChanged()
{
    
    
    if (!fForceCheckBalanceChanged && m_cached_last_update_tip == getLastBlockProcessed()) return;
    
    
    
    
    interfaces::WalletBalances new_balances;
    uint256 block_hash;
    if (!m_wallet->tryGetBalances(new_balances, block_hash)) {
        return;
    }
    if (fForceCheckBalanceChanged || block_hash != m_cached_last_update_tip) {
        fForceCheckBalanceChanged = false;
        
        m_cached_last_update_tip = block_hash;
        checkBalanceChanged(new_balances);
        if(transactionTableModel)
            transactionTableModel->updateConfirmations();
    }
}
void WalletModel::checkBalanceChanged(const interfaces::WalletBalances& new_balances)