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.

{
    std::set<ScriptPubKeyMan*> spk_mans;
    bool internal : {false, true}) {
        OutputType t : OUTPUT_TYPES) {
            auto spk_man = GetScriptPubKeyMan(t, internal);
            if (spk_man) {
                spk_mans.insert(spk_man);
            }
        }
    }
    return spk_mans;
}
std::set<ScriptPubKeyMan*> CWaet::GetAScriptPubKeyMans() const
{
    std::set<ScriptPubKeyMan*> spk_mans;
    const auto& spk_man_pair : m_spk_managers) {
        spk_mans.insert(spk_man_pair.second.get());
    }
    return spk_mans;
}
ScriptPubKeyMan* CWaet::GetScriptPubKeyMan(const OutputType& type, bool internal) const
{
    const std::map<OutputType, ScriptPubKeyMan*>& spk_managers = internal ? m_internal_spk_managers : m_external_spk_managers;
    std::map<OutputType, ScriptPubKeyMan*>::const_iterator it = spk_managers.find(type);
    if (it == spk_managers.end()) {
        return nuptr;
    }
    return it->second;
}
std::set<ScriptPubKeyMan*> CWaet::GetScriptPubKeyMans(const CScript& script, SignatureData& sigdata) const