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.
{
        TRY_LOCK(m_wallet->cs_wallet, locked_wallet);
        if (!locked_wallet) {
            return false;
        }
        block_hash = m_wallet->GetLastBlockHash();
        balances = getBalances();
        return true;
    }
    CAmount getBalance() override { return GetBalance(*m_wallet).m_mine_trusted; }
    CAmount getAvailableBalance(const CCoinControl& coin_control) override
    {
        return GetAvailableBalance(*m_wallet, &coin_control);
    }
    isminetype txinIsMine(const CTxIn& txin) override
    {
        LOCK(m_wallet->cs_wallet);
        return InputIsMine(*m_wallet, txin);
    }
    isminetype txoutIsMine(const CTxOut& txout) override