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 (internal && data.exists("label")) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "");
        }
        const std::string& label = data.exists("label") ? data["label"].get_str() : "";
        const bool add_keypool = data.exists("keypool") ? data["keypool"].get_bool() : false;
        // 
        if (add_keypool && !wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Keys can only be imported to the keypool when private keys are disabled");
        }
        ImportData import_data;
        std::map<CKeyID, CPubKey> pubkey_map;
        std::map<CKeyID, CKey> privkey_map;
        std::set<CScript> script_pub_keys;
        std::vector<CKeyID> ordered_pubkeys;
        bool have_solving_data;
        if (data.exists("scriptPubKey") && data.exists("desc")) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Both a descriptor and a scriptPubKey should not be provided.");
        } else if (data.exists("scriptPubKey")) {
            warnings = ProcessImportLegacy(import_data, pubkey_map, privkey_map, script_pub_keys, have_solving_data, data, ordered_pubkeys);
        } else if (data.exists("desc")) {
            warnings = ProcessImportDescriptor(import_data, pubkey_map, privkey_map, script_pub_keys, have_solving_data, data, ordered_pubkeys);
        } else {
            throw JSONRPCError(RPC_INVALID_PARAMETER, "Either a descriptor or scriptPubKey must be provided.");
        }
        // 
        if (wallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS) && !privkey_map.empty()) {
            throw JSONRPCError(RPC_WALLET_ERROR, "Cannot import private keys to a wallet with private keys disabled");
        }
        // 
        for (const CScript& script : script_pub_keys) {