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.
#include <qt/sendcoinsentry.h>
#include <qt/transactiontablemodel.h>
#include <qt/transactionview.h>
#include <qt/walletmodel.h>
#include <test/util/setup_common.h>
#include <validation.h>
#include <wallet/wallet.h>
#include <chrono>
#include <memory>
#include <QAbstractButton>
#include <QAction>
#include <QApplication>
#include <QCheckBox>
#include <QPushButton>
#include <QTimer>
#include <QVBoxLayout>
#include <QTextEdit>
#include <QListView>
#include <QDialogButtonBox>
using wallet::AddWallet;
using wallet::CWallet;
using wallet::CreateMockWalletDatabase;
using wallet::RemoveWallet;
using wallet::WALLET_FLAG_DESCRIPTORS;
using wallet::WalletContext;
using wallet::WalletDescriptor;
using wallet::WalletRescanReserver;
namespace
{
void ConfirmSend(QString* text = nullptr, bool cancel = false)