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::stringstream ret;
    for (const unsigned char c : str) {
        if (c <= 32 || c >= 128 || c == '%') {
            ret << '%' << HexStr(Span<const unsigned char>(&c, 1));
        } else {
            ret << c;
        }
    }
    return ret.str();
}
static std::string DecodeDumpString(const std::string &str) {
    std::stringstream ret;
    for (unsigned int pos = 0; pos < str.length(); pos++) {
        unsigned char c = str[pos];
        if (c == '%' && pos+2 < str.length()) {
            c = (((str[pos+1]>>6)*9+((str[pos+1]-'0')&15)) << 4) |
                ((str[pos+2]>>6)*9+((str[pos+2]-'0')&15));
            pos += 2;
        }
        ret << c;
    }
    return ret.str();
}
static bool GetWalletAddressesForKey(LegacyScriptPubKeyMan* spk_man, const CWallet& wallet, const CKeyID& keyid, std::string& strAddr, std::string& strLabel) EXCLUSIVE_LOCKS_REQUIRED(wallet.cs_wallet)
{