<!-- Describe the issue -->

When trying to sign a transaction in a encrypted wallet that is locked, version 0.16 would return the following error:

```"Please enter the wallet passphrase with walletpassphrase first."```

While doing exactly the same procedure against 0.17, the response is something like:

```json
"hex": "020000000183ac9cc1137c444f32356fb070ecba194c87a05e43674c06a55f5b1d0561eabc0000000000ffffffff0180626a94000000001600141875aa6ab19c2551c11759cf3e9f4dd7aa40bcf500000000",
       "complete": false,
       "errors": [
         {
           "txid": "bcea61051d5b5fa5064c67435ea0874c19baec70b06f35324f447c13c19cac83",
           "vout": 0,
           "witness": [
           ],
           "scriptSig": "",
           "sequence": 4294967295,
           "error": "Unable to sign input, invalid stack size (possibly missing key)"
         }
     ]

```

<!--- What behavior did you expect? -->

v0.17 should check if the wallet is locked before trying to sign the tx and return the same error as v0.16 for consistency reasons.
"3. include_watchonly (bool, optional, default=false) Whether to include watch-only addresses (see 'importaddress').\n"
            "4. address_filter    (string, optional) If present, only return information on this address.\n"
            "\nResult:\n"
            "[\n"
            "  {\n"
            "    \"involvesWatchonly\" : true,        (bool) Only returned if imported addresses were involved in transaction\n"
            "    \"address\" : \"receivingaddress\",  (string) The receiving address\n"
            "    \"amount\" : x.xxx,                  (numeric) The total amount in " + CURRENCY_UNIT + " received by the address\n"
            "    \"confirmations\" : n,               (numeric) The number of confirmations of the most recent transaction included\n"
            "    \"label\" : \"label\",               (string) The label of the receiving address. The default label is \"\".\n"
            "    \"txids\": [\n"
            "       \"txid\",                         (string) The ids of transactions received with the address \n"
            "       ...\n"
            "    ]\n"
            "  }\n"
            "  ,...\n"
            "]\n"
            "\nExamples:\n"
            + HelpExampleCli("listreceivedbyaddress", "")
            + HelpExampleCli("listreceivedbyaddress", "6 true")
            + HelpExampleRpc("listreceivedbyaddress", "6, true, true")
            + HelpExampleRpc("listreceivedbyaddress", "6, true, true, \"1M72Sfpbz1BPpXFHz9m3CdqATR44Jvaydd\"")
        );
    
    
    pwallet->BlockUntilSyncedToCurrentChain();
    LOCK2(cs_main, pwallet->cs_wallet);
    return ListReceived(pwallet, request.params, false);
}
static UniValue listreceivedbylabel(const JSONRPCRequest& request)