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/addresstablemodel.h>
#include <qt/bitcoinunits.h>
#include <qt/clientmodel.h>
#include <qt/coincontroldialog.h>
#include <qt/guiutil.h>
#include <qt/optionsmodel.h>
#include <qt/platformstyle.h>
#include <qt/sendcoinsentry.h>
#include <chainparams.h>
#include <interfaces/node.h>
#include <key_io.h>
#include <node/interface_ui.h>
#include <policy/fees.h>
#include <txmempool.h>
#include <validation.h>
#include <wallet/coincontrol.h>
#include <wallet/fees.h>
#include <wallet/wallet.h>
#include <array>
#include <chrono>
#include <fstream>
#include <memory>
#include <QFontMetrics>
#include <QScrollBar>
#include <QSettings>
#include <QTextDocument>
using wallet::CCoinControl;
using wallet::DEFAULT_PAY_TX_FEE;
static constexpr std::array confTargets{2, 4, 6, 12, 24, 48, 144, 504, 1008};
int getConfTargetForIndex(int index) {