Create a wallet as follows:

```sh
$ bitcoin-cli createwallet "watchonly" true
$ bitcoin-cli -rpcwallet=watchonly getwalletinfo
{
   ...
   "private_keys_enabled": false
}
```

The following should fail, but doesn't:

```sh
$ bitcoin-cli -rpcwallet=watchonly encryptwallet 1234
wallet encrypted; The keypool has been flushed and a new HD seed was generated (if you are using HD). You need to make a new backup.
```

It partially fails silently, because it doesn't actually add a seed. But it does ask for a password when calling `dumpwallet`, which doesn't make sense because we currently don't encrypt anything other than private keys.  
RPCHelpMan{"listwalletdir",
                "Returns a list of wallets in the wallet directory.\n",
                {},
                RPCResult{
            "{\n"
            "  \"wallets\" : [                (json array of objects)\n"
            "    {\n"
            "      \"name\" : \"name\"          (string) The wallet name\n"
            "    }\n"
            "    ,...\n"
            "  ]\n"
            "}\n"
                },
                RPCExamples{
                    HelpExampleCli("listwalletdir", "")
            + HelpExampleRpc("listwalletdir", "")
                },
            }.ToString());
    }
    UniValue wallets(UniValue::VARR);
    for (const auto& path : ListWalletDir()) {
        UniValue wallet(UniValue::VOBJ);
        wallet.pushKV("name", path.string());
        wallets.push_back(wallet);
    }
    UniValue result(UniValue::VOBJ);
    result.pushKV("wallets", wallets);
    return result;
}
static UniValue listwallets(const JSONRPCRequest& request)