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.
{
        LOCK(m_wallet->cs_wallet);
        std::set<WalletTx> result;
        for (const auto& entry : m_wallet->mapWallet) {
            result.emplace(MakeWalletTx(*m_wallet, entry.second));
        }
        return result;
    }
    bool tryGetTxStatus(const uint256& txid,
        interfaces::WalletTxStatus& tx_status,
        int& num_blocks,
        int64_t& block_time) override
    {
        TRY_LOCK(m_wallet->cs_wallet, locked_wallet);
        if (!locked_wallet) {
            return false;
        }
        auto mi = m_wallet->mapWallet.find(txid);
        if (mi == m_wallet->mapWallet.end()) {
            return false;
        }
        num_blocks = m_wallet->GetLastBlockHeight();
        block_time = -1;
        CHECK_NONFATAL(m_wallet->chain().findBlock(m_wallet->GetLastBlockHash(), FoundBlock().time(block_time)));
        tx_status = MakeWalletTxStatus(*m_wallet, mi->second);
        return true;
    }
    WalletTx getWalletTxDetails(const uint256& txid,