### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I'm executing a state machine using the following definition:

```json
{
  "StartAt": "Parallel",
  "States": {
    "Parallel": {
      "Type": "Parallel",
      "Branches": [
        {
          "StartAt": "BranchA",
          "States": {
            "BranchA": {
              "Type": "Pass",
              "Result": {
                "branch": "A"
              },
              "End": true
            }
          }
        },
        {
          "StartAt": "BranchB",
          "States": {
            "BranchB": {
              "Type": "Pass",
              "Result": {
                "branch": "B"
              },
              "End": true
            }
          }
        }
      ],
      "End": true
    }
  }
}
```

I get the following output:

```json
[
  {
    "branch": "B"
  },
  {
    "branch": "A"
  }
]
```

The results are not in the correct order. The result from branch A should always be first even when the branch A is slower, and the result from branch B should always be second.

### Expected Behavior

The output should be:

```json
[
  {
    "branch": "A"
  },
  {
    "branch": "B"
  }
]
```

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

Create and execute a state machine using the provided definition.

### Environment

```markdown
- LocalStack: 3.0.3.dev20231207105008
```


### Anything else?

_No response_
execution_history = aws_client.stepfunctions.get_execution_history(
            executionArn=execution_arn
        )
        map_run_arn = JSONPathUtils.extract_json(
            "$..mapRunStartedEventDetails.mapRunArn", execution_history
        )
        sfn_snapshot.add_transformer(sfn_snapshot.transform.sfn_map_run_arn(map_run_arn, 0))
        
        
        
        output_str = execution_history["events"][-1]["executionSucceededEventDetails"]["output"]
        output_json = json.loads(output_str)
        output_norm = []
        for output_value in output_json:
            norm_output_value = OrderedDict()
            norm_output_value["Etag"] = f"<Etag-{output_value['Key']}>"
            norm_output_value["LastModified"] = "<date>"
            norm_output_value["Key"] = output_value["Key"]
            norm_output_value["Size"] = output_value["Size"]
            norm_output_value["StorageClass"] = output_value["StorageClass"]
            output_norm.append(norm_output_value)
        output_norm.sort(key=lambda value: value["Key"])
        output_norm_str = json.dumps(output_norm)
        execution_history["events"][-2]["stateExitedEventDetails"]["output"] = output_norm_str
        execution_history["events"][-1]["executionSucceededEventDetails"][
            "output"
        ] = output_norm_str
        sfn_snapshot.match("get_execution_history", execution_history)
    @markers.aws.validated
    def test_map_item_reader_base_csv_headers_first_line(