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->GetAddressReceiveRequests();
    }
    bool setAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& value) override {
        LOCK(m_wallet->cs_wallet);
        WalletBatch batch{m_wallet->GetDatabase()};
        return m_wallet->SetAddressReceiveRequest(batch, dest, id, value);
    }
    bool displayAddress(const CTxDestination& dest) override
    {
        LOCK(m_wallet->cs_wallet);
        return m_wallet->DisplayAddress(dest);
    }
    bool lockCoin(const COutPoint& output, const bool write_to_db) override
    {
        LOCK(m_wallet->cs_wallet);
        std::unique_ptr<WalletBatch> batch = write_to_db ? std::make_unique<WalletBatch>(m_wallet->GetDatabase()) : nullptr;
        return m_wallet->LockCoin(output, batch.get());
    }
    bool unlockCoin(const COutPoint& output) override
    {
        LOCK(m_wallet->cs_wallet);
        std::unique_ptr<WalletBatch> batch = std::make_unique<WalletBatch>(m_wallet->GetDatabase());
        return m_wallet->UnlockCoin(output, batch.get());
    }
    bool isLockedCoin(const COutPoint& output) override