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.

***

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.
{
    QByteArray transaction_array; 
    {
        std::vector<std::pair<std::string, std::string>> vOrderForm;
        for (const SendCoinsRecipient &rcp : transaction.getRecipients())
        {
            if (!rcp.message.isEmpty()) 
                vOrderForm.emplace_back("Message", rcp.message.toStdString());
        }
        auto& newTx = transaction.getWtx();
        wallet().commitTransaction(newTx, {}, std::move(vOrderForm));
        CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
        ssTx << *newTx;
        transaction_array.append((const char*)ssTx.data(), ssTx.size());
    }
    
    
    for (const SendCoinsRecipient &rcp : transaction.getRecipients())
    {
        {