The `dumpwallet` RPC command throws an error at the signet node and stops it.
~~This does not happen in mainnet or testnet, where the command worked successfully in my tests..~~
Originally this error was only happening on signet, but it also happened on testnet after it worked successfully for a while.

**Expected behavior**

The RPC `dumpwallet` command is expected to return a success message and create the dump file that contains the private keys.

**Actual behavior**

The command returns an error on client side (`bitcoin-cli`):
`error: timeout on transient error: Could not connect to the server 127.0.0.1:38332 (error code 1 - "EOF reached")
Make sure the bitcoind server is running and that you are connecting to the correct RPC port.`

And it throws an error at the signet node and stops it.

```
POTENTIAL DEADLOCK DETECTED
Previous lock order was:
  'cs_wallet' in wallet/wallet.cpp:2860 (in thread 'httpworker.1')
  (2) '::cs_main' in node/interfaces.cpp:687 (in thread 'httpworker.1')
  'm_node.mempool->cs' in node/interfaces.cpp:687 (in thread 'httpworker.1')
  'cs_wallet' in wallet/wallet.cpp:1204 (in thread 'httpworker.1')
  (1) 'cs_KeyStore' in script/signingprovider.cpp:165 (in thread 'httpworker.1')
Current lock order is:
  'wallet.cs_wallet' in wallet/rpcdump.cpp:743 (in thread 'httpworker.3')
  (1) 'spk_man.cs_KeyStore' in wallet/rpcdump.cpp:743 (in thread 'httpworker.3')
  (1) 'spk_man->cs_KeyStore' in wallet/wallet.cpp:2303 (in thread 'httpworker.3')
  (2) 'cs_main' in node/interfaces.cpp:493 (in thread 'httpworker.3')
Assertion failed: detected inconsistent lock order for 'cs_main' in node/interfaces.cpp:493 (in thread 'httpworker.3'), details in debug log.
Aborted (core dumped)
```

**To reproduce**

Start the node on signet mode:
`bitcoind -signet`

And dump an existing wallet:
`bitcoin-cli -signet -rpcwallet="legacy_wallet_01" dumpwallet "filename"`

**System information**

The bitcoin node was compiled from master (commit: `df2b5dadfb2dc21b05e5a60b71987fb5b96201f5`)
Ubuntu 20.04, 8 CPUs, 12 GiB RAM and SSD.

if (!subscript) return "missing redeemscript";
        if (CScriptID(*subscript) != id) return "redeemScript does not match the scriptPubKey";
        import_data.import_scripts.emplace(*subscript);
        return RecurseImportData(*subscript, import_data, ScriptContext::P2SH);
    }
    case TxoutType::MULTISIG: {
        for (size_t i = 1; i + 1< solverdata.size(); ++i) {
            CPubKey pubkey(solverdata[i]);
            import_data.used_keys.emplace(pubkey.GetID(), false);
        }
        return "";
    }
    case TxoutType::WITNESS_V0_SCRIPTHASH: {
        if (script_ctx == ScriptContext::WITNESS_V0) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Trying to nest P2WSH inside another P2WSH");
        uint256 fullid(solverdata[0]);
        CScriptID id;
        CRIPEMD160().Write(fullid.begin(), fullid.size()).Finalize(id.begin());
        auto subscript = std::move(import_data.witnessscript); // 
        if (!subscript) return "missing witnessscript";
        if (CScriptID(*subscript) != id) return "witnessScript does not match the scriptPubKey or redeemScript";
        if (script_ctx == ScriptContext::TOP) {
            import_data.import_scripts.emplace(script); // 
        }
        import_data.import_scripts.emplace(*subscript);
        return RecurseImportData(*subscript, import_data, ScriptContext::WITNESS_V0);
    }
    case TxoutType::WITNESS_V0_KEYHASH: {
        if (script_ctx == ScriptContext::WITNESS_V0) throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Trying to nest P2WPKH inside P2WSH");
        CKeyID id = CKeyID(uint160(solverdata[0]));
        import_data.used_keys[id] = true;