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.

CHECK_NONFATAL(key.VerifyPubKey(pubkey));
            CKeyID keyid = pubkey.GetID();
            pwallet->WalletLogPrintf("Importing %s...\n", EncodeDestination(PKHash(keyid)));
            if (!pwallet->ImportPrivKeys({{keyid, key}}, time)) {
                pwallet->WalletLogPrintf("Error importing key for %s\n", EncodeDestination(PKHash(keyid)));
                fGood = false;
                continue;
            }
            if (has_label)
                pwallet->SetAddressBook(PKHash(keyid), label, "receive");
            nTimeBegin = std::min(nTimeBegin, time);
            progress++;
        }
        for (const auto& script_pair : scripts) {
            pwallet->chain().showProgress("", std::max(50, std::min(75, (int)((progress / total) * 100) + 50)), false);
            const CScript& script = script_pair.first;
            int64_t time = script_pair.second;
            if (!pwallet->ImportScripts({script}, time)) {
                pwallet->WalletLogPrintf("Error importing script %s\n", HexStr(script));
                fGood = false;
                continue;
            }
            if (time > 0) {
                nTimeBegin = std::min(nTimeBegin, time);
            }
            progress++;
        }
        pwallet->chain().showProgress("", 100, false); // 
    }
    pwallet->chain().showProgress("", 100, false); //