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.
"  \"isscript\" : true|false,      (boolean) If the key is a script\n"
            "  \"iswitness\" : true|false,     (boolean) If the address is a witness address\n"
            "  \"witness_version\" : version   (numeric, optional) The version number of the witness program\n"
            "  \"witness_program\" : \"hex\"     (string, optional) The hex value of the witness program\n"
            "  \"script\" : \"type\"             (string, optional) The output script type. Only if \"isscript\" is true and the redeemscript is known. Possible types: nonstandard, pubkey, pubkeyhash, scripthash, multisig, nulldata, witness_v0_keyhash, witness_v0_scripthash, witness_unknown\n"
            "  \"hex\" : \"hex\",                (string, optional) The redeemscript for the p2sh address\n"
            "  \"pubkeys\"                     (string, optional) Array of pubkeys associated with the known redeemscript (only if \"script\" is \"multisig\")\n"
            "    [\n"
            "      \"pubkey\"\n"
            "      ,...\n"
            "    ]\n"
            "  \"sigsrequired\" : xxxxx        (numeric, optional) Number of signatures required to spend multisig output (only if \"script\" is \"multisig\")\n"
            "  \"pubkey\" : \"publickeyhex\",    (string, optional) The hex value of the raw public key, for single-key addresses (possibly embedded in P2SH or P2WSH)\n"
            "  \"embedded\" : {...},           (object, optional) Information about the address embedded in P2SH or P2WSH, if relevant and known. It includes all getaddressinfo output fields for the embedded address, excluding metadata (\"timestamp\", \"hdkeypath\", \"hdseedid\") and relation to the wallet (\"ismine\", \"iswatchonly\", \"account\").\n"
            "  \"iscompressed\" : true|false,  (boolean) If the address is compressed\n"
            "  \"label\" :  \"label\"         (string) The label associated with the address, \"\" is the default account\n"
            "  \"account\" : \"account\"         (string) DEPRECATED. This field will be removed in V0.18. To see this deprecated field, start bitcoind with -deprecatedrpc=accounts. The account associated with the address, \"\" is the default account\n"
            "  \"timestamp\" : timestamp,      (number, optional) The creation time of the key if available in seconds since epoch (Jan 1 1970 GMT)\n"
            "  \"hdkeypath\" : \"keypath\"       (string, optional) The HD keypath if the key is HD and available\n"
            "  \"hdseedid\" : \"<hash160>\"      (string, optional) The Hash160 of the HD seed\n"
            "  \"hdmasterkeyid\" : \"<hash160>\" (string, optional) alias for hdseedid maintained for backwards compatibility. Will be removed in V0.18.\n"
            "  \"labels\"                      (object) Array of labels associated with the address.\n"
            "    [\n"
            "      { (json object of label data)\n"
            "        \"name\": \"labelname\" (string) The label\n"
            "        \"purpose\": \"string\" (string) Purpose of address (\"send\" for sending address, \"receive\" for receiving address)\n"
            "      },...\n"
            "    ]\n"
            "}\n"
            "\nExamples:\n"