addmultisigaddress creates an address respecting the setting, being unable to generate a specific type of address without also adding it to the wallet seems wrong.

I suppose in the future `addresstype` may be refactored to be wallet-specific, which would leave this non-wallet rpc call without an argument. Perhaps there should just be an optional parameter to set it.
pwallet->SetHDSeed(master_pub_key);
    if (flush_key_pool) pwallet->NewKeyPool();
    return NullUniValue;
}
extern UniValue abortrescan(const JSONRPCRequest& request); 
extern UniValue dumpprivkey(const JSONRPCRequest& request); 
extern UniValue importprivkey(const JSONRPCRequest& request);
extern UniValue importaddress(const JSONRPCRequest& request);
extern UniValue importpubkey(const JSONRPCRequest& request);
extern UniValue dumpwallet(const JSONRPCRequest& request);
extern UniValue importwallet(const JSONRPCRequest& request);
extern UniValue importprunedfunds(const JSONRPCRequest& request);
extern UniValue removeprunedfunds(const JSONRPCRequest& request);
extern UniValue importmulti(const JSONRPCRequest& request);
extern UniValue rescanblockchain(const JSONRPCRequest& request);
static const CRPCCommand commands[] =
{ 
    
    { "rawtransactions",    "fundrawtransaction",               &fundrawtransaction,            {"hexstring","options","iswitness"} },
    { "hidden",             "resendwallettransactions",         &resendwallettransactions,      {} },
    { "wallet",             "abandontransaction",               &abandontransaction,            {"txid"} },
    { "wallet",             "abortrescan",                      &abortrescan,                   {} },
    { "wallet",             "addmultisigaddress",               &addmultisigaddress,            {"nrequired","keys","label|account","address_type"} },
    { "hidden",             "addwitnessaddress",                &addwitnessaddress,             {"address","p2sh"} },
    { "wallet",             "backupwallet",                     &backupwallet,                  {"destination"} },
    { "wallet",             "bumpfee",                          &bumpfee,                       {"txid", "options"} },
    { "wallet",             "createwallet",                     &createwallet,                  {"wallet_name"} },
    { "wallet",             "dumpprivkey",                      &dumpprivkey,                   {"address"}  },
    { "wallet",             "dumpwallet",                       &dumpwallet,                    {"filename"} },
    { "wallet",             "encryptwallet",                    &encryptwallet,                 {"passphrase"} },