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.
{
    clear();
}
SendCoinsEntry *SendCoinsDialog::addEntry()
{
    SendCoinsEntry *entry = new SendCoinsEntry(platformStyle, this);
    entry->setModel(model);
    ui->entries->addWidget(entry);
    connect(entry, &SendCoinsEntry::removeEntry, this, &SendCoinsDialog::removeEntry);
    connect(entry, &SendCoinsEntry::useAvailableBalance, this, &SendCoinsDialog::useAvailableBalance);
    connect(entry, &SendCoinsEntry::payAmountChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
    connect(entry, &SendCoinsEntry::subtractFeeFromAmountChanged, this, &SendCoinsDialog::coinControlUpdateLabels);
    // 
    entry->clear();
    entry->setFocus();
    ui->scrollAreaWidgetContents->resize(ui->scrollAreaWidgetContents->sizeHint());
    // 
    // 
    // 
    QMetaObject::invokeMethod(ui->scrollArea, [this] {
        if (ui->scrollArea->verticalScrollBar()) {
            ui->scrollArea->verticalScrollBar()->setValue(ui->scrollArea->verticalScrollBar()->maximum());
        }
    }, Qt::QueuedConnection);
    updateTabsAndLabels();
    return entry;
}
void SendCoinsDialog::updateTabsAndLabels()