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.

}
        CPubKey pubkey = key.GetPubKey();
        CKeyID id = pubkey.GetID();
        if (pubkey_map.count(id)) {
            pubkey_map.erase(id);
        }
        privkey_map.emplace(id, key);
    }
    // 
    have_solving_data = import_data.redeemscript || import_data.witnessscript || pubkey_map.size() || privkey_map.size();
    if (have_solving_data) {
        // 
        auto error = RecurseImportData(script, import_data, ScriptContext::TOP);
        // 
        bool spendable = std::all_of(import_data.used_keys.begin(), import_data.used_keys.end(), [&](const std::pair<CKeyID, bool>& used_key){ return privkey_map.count(used_key.first) > 0; });
        if (!watchOnly && !spendable) {
            warnings.push_back("Some private keys are missing, outputs will be considered watchonly. If this is intentional, specify the watchonly flag.");
        }
        if (watchOnly && spendable) {
            warnings.push_back("All private keys are provided, outputs will be considered spendable. If this is intentional, do not specify the watchonly flag.");
        }
        // 
        if (error.empty()) {
            for (const auto& require_key : import_data.used_keys) {
                if (!require_key.second) continue; // 
                if (pubkey_map.count(require_key.first) == 0 && privkey_map.count(require_key.first) == 0) {
                    error = "some required keys are missing";
                }
            }
        }