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
{
        for (const CRPCCommand& command : GetWalletRPCCommands()) {
            m_rpc_commands.emplace_back(command.category, command.name, [this, &command](const JSONRPCRequest& request, UniValue& result, bool last_handler) {
                JSONRPCRequest wallet_request = request;
                wallet_request.context = &m_context;
                return command.actor(wallet_request, result, last_handler);
            }, command.argNames, command.unique_id);
            m_rpc_handlers.emplace_back(m_context.chain->handleRpc(m_rpc_commands.back()));
        }
    }
    bool verify() override { return VerifyWallets(m_context); }
    bool load() override { return LoadWallets(m_context); }
    void start(CScheduler& scheduler) override { return StartWallets(m_context, scheduler); }
    void flush() override { return FlushWallets(m_context); }
    void stop() override { return StopWallets(m_context); }
    void setMockTime(int64_t time) override { return SetMockTime(time); }
    
    util::Result<std::unique_ptr<Wallet>> createWallet(const std::string& name, const SecureString& passphrase, uint64_t wallet_creation_flags, std::vector<bilingual_str>& warnings) override
    {
        DatabaseOptions options;
        DatabaseStatus status;
        ReadDatabaseArgs(*m_context.args, options);
        options.require_create = true;
        options.create_flags = wallet_creation_flags;
        options.create_passphrase = passphrase;
        bilingual_str error;
        util::Result<std::unique_ptr<Wallet>> wallet{MakeWallet(m_context, CreateWallet(m_context, name, true, options, status, error, warnings))};
        return wallet ? std::move(wallet) : util::Error{error};
    }
    util::Result<std::unique_ptr<Wallet>> loadWallet(const std::string& name, std::vector<bilingual_str>& warnings) override