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
{
    if (options.exists("conf_target") || options.exists("estimate_mode")) {
        if (!conf_target.isNull() || !estimate_mode.isNull()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Pass conf_target and estimate_mode either as arguments or in the options object, but not both");
        }
    } else {
        options.pushKV("conf_target", conf_target);
        options.pushKV("estimate_mode", estimate_mode);
    }
    if (options.exists("fee_rate")) {
        if (!fee_rate.isNull()) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Pass the fee_rate either as an argument, or in the options object, but not both");
        }
    } else {
        options.pushKV("fee_rate", fee_rate);
    }
    if (!options["conf_target"].isNull() && (options["estimate_mode"].isNull() || (options["estimate_mode"].get_str() == "unset"))) {
        throw JSONRPCError(RPC_INVALID_PARAMETER, "Specify estimate_mode");
    }
}
static UniValue FinishTransaction(const std::shared_ptr<CWallet> pwallet, const UniValue& options, const CMutableTransaction& rawTx)
{
    
    PartiallySignedTransaction psbtx(rawTx);
    
    
    bool complete;