Give an option to stop pretty print in the proxy response

[cesczacks]

I am using the mountebank to make the request proxy to the LocalStack (an AWS emulator tool).
The behavior changed since mountebank version 2.7.0 because a more pretty printed response was responded that changes the Content-Length value in the response header.
The difference can be seen in the log part..Obviously, in mountebank v2.7.0 or onwards, The json in the response body is prettied by line break.
Can we have an option for user to choose whether to use pretty body response or not? Thanks

Expected behaviour

Print the raw string JSON in the response
...

Actual behaviour

a pretty printed JSON response was responsed
...

Steps to reproduce

1. Run the below docker compose

services:
  localstack:
    image: localstack/localstack:3.8.1-arm64
    container_name: localstack
    healthcheck:
      retries: 3
    environment:
      SERVICES: dynamodb
      LS_LOG: trace
    ports:
      - 4566:4566
      - 4572:4572

  mountebank:
    # image: bbyars/mountebank:2.6.0
    image: bbyars/mountebank:2.7.0
    container_name: mountebank
    ports:
      - 2525:2525
      - 8080:8080
    volumes:
      - ./imposters.ejs:/mountebank/imposters.ejs
    entrypoint:
      - mb
      - --configfile
      - /mountebank/imposters.ejs
      - --allowInjection
      - --loglevel
      - debug
...
with imposter
``` json
{
    "imposters": [
      {
        "port": 8080,
        "protocol": "http",
        "name": "S3 Proxy",
        "stubs": [
          {
            "responses": [
              {
                "proxy": {
                  "to": "http://localstack:4566",
                  "mode": "proxyAlways"
                }
              }
            ]
          }
        ]
      }
    ]
  }
  

2. Make a request using AWS .NET SDK

using System.Text.Json;
using Amazon;
using Amazon.DynamoDBv2;
using Amazon.DynamoDBv2.Model;

var client = new AmazonDynamoDBClient(new AmazonDynamoDBConfig
{
    ServiceURL = "http://localhost:8080",
    AuthenticationRegion = "eu-west-1",
    DisableLogging = false,
    MaxErrorRetry = 3
});

try
{
    Console.WriteLine("Fetching DynamoDB...");
    var result = await client.GetItemAsync("Devices", new Dictionary<string, AttributeValue>()
    {
        { "Serial", new AttributeValue { S = "xxx" } }
    });
    Console.WriteLine("Done");
    Console.WriteLine(JsonSerializer.Serialize(result));
}
catch (Exception e)
{
    Console.WriteLine(e);
    throw;
}

3. An error throws that indicates the CRC value diffs

System.IO.IOException: CRC value returned with response does not match the computed CRC value for the returned response body.

Software versions used

OS         : MacOS
mountebank : 2.7.0
node.js    : v22.1.0
  (only if installed via npm)
Installation method :
  (npm, zip, tar, pkg, deb, rpm)

Log contents in mb.log when running mb --loglevel debug

// mountebank 2.6.0 .NET SDK
mountebank  | debug: [http:8080 S3 Proxy] ::ffff:192.168.65.1:45167 <= {"statusCode":200,"headers":{"Connection":"close","Server":"TwistedWeb/24.3.0","Date":"Thu, 24 Oct 2024 07:06:45 GMT","Content-Type":"application/x-amz-json-1.0","Content-Length":397,"x-amzn-requestid":"ed933fb1-da80-45f2-a192-4afaff2cb054","x-amz-crc32":"3479715746"},"body":"{\"Item\": {\"Timezone\": {\"S\": \"xx\"}, \"Serial\": {\"S\": \"xxxx\"}, \"Data\": {\"S\": \"{\\\"Serial\\\":\\\"xxxx\\\",\\\"Name\\\":\\\"xxxx\\\",\\\"ScaleUnit\\\":\\\"AWS-IOT\\\",\\\"Variant\\\":\\\"E\\\",\\\"Version\\\":\\\"xx\\\",\\\"AutoUpdate\\\":true,\\\"NewVersionAvailable\\\":false,\\\"Provisioned\\\":true}\"}}}","_mode":"text"}

// mountebank 2.7.0 .NET SDK
mountebank  | debug: [http:8080 S3 Proxy] ::ffff:192.168.65.1:29435 <= {"statusCode":200,"headers":{"Connection":"close","Server":"TwistedWeb/24.3.0","Date":"Thu, 24 Oct 2024 07:08:09 GMT","Content-Type":"application/x-amz-json-1.0","Content-Length":469,"x-amzn-requestid":"30817988-5174-45e0-9b87-1ca36b7cf7f6","x-amz-crc32":"3479715746"},"body":"{\n    \"Item\": {\n        \"Timezone\": {\n            \"S\": \"xx\"\n        },\n        \"Serial\": {\n            \"S\": \"xxxx\"\n        },\n        \"Data\": {\n            \"S\": \"{\\\"Serial\\\":\\\"xxxx\\\",\\\"Name\\\":\\\"xxxx\\\",\\\"ScaleUnit\\\":\\\"AWS-IOT\\\",\\\"Variant\\\":\\\"E\\\",\\\"Version\\\":\\\"xx\\\",\\\"AutoUpdate\\\":true,\\\"NewVersionAvailable\\\":false,\\\"Provisioned\\\":true}\"\n        }\n    }\n}","_mode":"text"}

// mountebank 2.7.0 NODE.SDK
mountebank  | debug: [http:8080 S3 Proxy] ::ffff:192.168.65.1:38636 <= {"statusCode":200,"headers":{"Server":"TwistedWeb/24.3.0","Date":"Thu, 24 Oct 2024 07:21:57 GMT","Content-Type":"application/x-amz-json-1.0","Content-Length":469,"x-amzn-requestid":"284a9a12-b05a-4c12-94d0-30eb80efd458","x-amz-crc32":"3479715746","Connection":"close"},"body":"{\n    \"Item\": {\n        \"Timezone\": {\n            \"S\": \"xx\"\n        },\n        \"Serial\": {\n            \"S\": \"xxxx\"\n        },\n        \"Data\": {\n            \"S\": \"{\\\"Serial\\\":\\\"xxxx\\\",\\\"Name\\\":\\\"xxxx\\\",\\\"ScaleUnit\\\":\\\"AWS-IOT\\\",\\\"Variant\\\":\\\"E\\\",\\\"Version\\\":\\\"xx\\\",\\\"AutoUpdate\\\":true,\\\"NewVersionAvailable\\\":false,\\\"Provisioned\\\":true}\"\n        }\n    }\n}","_mode":"text"}˜