External inputs are currently only supported for initial transaction creation functions. Extend `solving_data` arguments as necessary to support fee bumping wallet transactions with non-wallet inputs.

https://github.com/bitcoin/bitcoin/pull/17211#issuecomment-897653994
{
        LOCK(m_wallet->cs_wallet);
        return m_wallet->IsLockedCoin(output);
    }
    void listLockedCoins(std::vector<COutPoint>& outputs) override
    {
        LOCK(m_wallet->cs_wallet);
        return m_wallet->ListLockedCoins(outputs);
    }
    util::Result<CTransactionRef> createTransaction(const std::vector<CRecipient>& recipients,
        const CCoinControl& coin_control,
        bool sign,
        int& change_pos,
        CAmount& fee) override
    {
        LOCK(m_wallet->cs_wallet);
        auto res = CreateTransaction(*m_wallet, recipients, change_pos,
                                     coin_control, sign);
        if (!res) return util::Error{util::ErrorString(res)};
        const auto& txr = *res;
        fee = txr.fee;
        change_pos = txr.change_pos;
        return txr.tx;
    }
    void commitTransaction(CTransactionRef tx,