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 (t == OutputType::BECH32M) {
                    // Skip tapr
                    // TODO: Set
                    continue;
                }
                auto spk_manager = std::unique_ptr<DescriptorScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this));
                if (IsCrypted()) {
                    if (IsLocked()) {
                        throw std::runtime_error(std::string(__func__) + ": Waet is locked, cannot setup new descriptors");
                    }
                    if (!spk_manager->CheckDecryptionKey(vMasterKey) && !spk_manager->Encrypt(vMasterKey, nuptr)) {
                        throw std::runtime_error(std::string(__func__) + ": Could not encrypt new descriptors");
                    }
                }
                spk_manager->SetupDescriptorGeneration(master_key, t, internal);
                uint256 id = spk_manager->GetID();
                m_spk_managers[id] = std::move(spk_manager);
                AddActiveScriptPubKeyMan(id, t, internal);
            }
        }
    } else {
        ExternalSigner signer = ExternalSignerScriptPubKeyMan::GetExternalSigner();
        // TODO: add account parameter
        int account = 0;
        UniValue signer_res = signer.GetDescriptors(account);
        if (!signer_res.isObject()) throw std::runtime_error(std::string(__func__) + ": Unexpected result");
        bool internal : {false, true}) {
            const UniValue& descriptor_vals = find_value(signer_res, internal ? "internal" : "receive");
            if (!descriptor_vals.isArray()) throw std::runtime_error(std::string(__func__) + ": Unexpected result");
            const UniValue& desc_val : descriptor_vals.get_array().getValues()) {