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.
bool commitBumpTransaction(const uint256& txid,
        CMutableTransaction&& mtx,
        std::vector<bilingual_str>& errors,
        uint256& bumped_txid) override
    {
        return feebumper::CommitTransaction(*m_wallet.get(), txid, std::move(mtx), errors, bumped_txid) ==
               feebumper::Result::OK;
    }
    CTransactionRef getTx(const uint256& txid) override
    {
        LOCK(m_wallet->cs_wallet);
        auto mi = m_wallet->mapWallet.find(txid);
        if (mi != m_wallet->mapWallet.end()) {
            return mi->second.tx;
        }
        return {};
    }
    WalletTx getWalletTx(const uint256& txid) override
    {
        LOCK(m_wallet->cs_wallet);
        auto mi = m_wallet->mapWallet.find(txid);
        if (mi != m_wallet->mapWallet.end()) {
            return MakeWalletTx(*m_wallet, mi->second);
        }
        return {};
    }
    std::set<WalletTx> getWalletTxs() override