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<!-- Describe the issue -->

**Expected behavior**

When I make a json-rpc call to `getblock` with:

```json
{
    "jsonrpc": "1.0",
    "id": "curltest",
    "method": "getblock",
    "params": ["37351c7060ec3a149af1bbc9ebcc436c0ee652f96559ef1fe9bc45d11000f061", "2"]
}
```
An error should be returned with the [expected data type](https://developer.bitcoin.org/reference/rpc/getblock.html#argument-2-verbosity)(number) for `verbosity`.
<!--- What behavior did you expect? -->

**Actual behavior**

<!--- What was the actual behavior (provide screenshots if the issue is GUI-related)? -->

Received `"message": "JSON value is not a boolean as expected"` as an error message which is not the [expected data type](number) (https://developer.bitcoin.org/reference/rpc/getblock.html#argument-2-verbosity) for `verbosity`

**To reproduce**

Use this curl on a node

```
curl --location --request POST "127.0.0.1:8332" \
--header "Content-Type: application/json" \
--header "Authorization: Basic YOUR_AUTH" \
--data "{
    \"jsonrpc\": \"1.0\",
    \"id\": \"curltest\",
    \"method\": \"getblock\",
    \"params\": [\"37351c7060ec3a149af1bbc9ebcc436c0ee652f96559ef1fe9bc45d11000f061\", \"2\"]
}"
```

**System information**
* self-compiled

<!-- What version of Bitcoin Core are you using, where did you get it (website, self-compiled, etc)? -->

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<!-- Any extra information that might be useful in the debugging process. -->
<!--- This is normally the contents of a `debug.log` or `config.log` file. Raw text or a link to a pastebin type site are preferred. -->

{
    return RPCHelpMan{"getblockheader",
                "\nIf verbose is false, returns a string that is serialized, hex-encoded data for blockheader 'hash'.\n"
                "If verbose is true, returns an Object with information about blockheader <hash>.\n",
                {
                    {"blockhash", RPCArg::Type::STR_HEX, RPCArg::Optional::NO, "The block hash"},
                    {"verbose", RPCArg::Type::BOOL,  "true", "true for a json object, false for the hex-encoded data"},
                },
                {
                    RPCResult{"for verbose = true",
                        RPCResult::Type::OBJ, "", "",
                        {
                            {RPCResult::Type::STR_HEX, "hash", "the block hash (same as provided)"},
                            {RPCResult::Type::NUM, "confirmations", "The number of confirmations, or -1 if the block is not on the main chain"},
                            {RPCResult::Type::NUM, "height", "The block height or index"},
                            {RPCResult::Type::NUM, "version", "The block version"},
                            {RPCResult::Type::STR_HEX, "versionHex", "The block version formatted in hexadecimal"},
                            {RPCResult::Type::STR_HEX, "merkleroot", "The merkle root"},
                            {RPCResult::Type::NUM_TIME, "time", "The block time expressed in " + UNIX_EPOCH_TIME},
                            {RPCResult::Type::NUM_TIME, "mediantime", "The median block time expressed in " + UNIX_EPOCH_TIME},
                            {RPCResult::Type::NUM, "nonce", "The nonce"},
                            {RPCResult::Type::STR_HEX, "bits", "The bits"},
                            {RPCResult::Type::NUM, "difficulty", "The difficulty"},
                            {RPCResult::Type::STR_HEX, "chainwork", "Expected number of hashes required to produce the current chain"},
                            {RPCResult::Type::NUM, "nTx", "The number of transactions in the block"},
                            {RPCResult::Type::STR_HEX, "previousblockhash",  true, "The hash of the previous block (if available)"},
                            {RPCResult::Type::STR_HEX, "nextblockhash",  true, "The hash of the next block (if available)"},
                        }},
                    RPCResult{"for verbose=false",