### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

Currently, when passing `$$.Execution.StartTime` as a parameter to a SFN lambda, it is coming in in the format `HH:MM:SS.###`.

### Expected Behavior

`$$.Execution.StartTime` should be an ISO 8601 datetime string.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

This is run in a docker compose file.

Step function definition is

```json
{
  "Comment": "Sample SFN",
  "StartAt": "SampleLambda",
  "States": {    
    "SampleLambda": {
      "Type": "Task",
      "Resource": "arn:aws:states:::lambda:invoke",
      "End": true,
      "Parameters": {
        "FunctionName": "Sample-Function",
        "Payload": {
          "data": {
            "startDateTime.$": "$$.Execution.StartTime"
          }
        }
      }
    }
  }
}
```

### Environment

```markdown
- OS: Mac OS Ventura 13.6.1
- LocalStack:
LocalStack version: 3.0.1.dev
LocalStack build date: 2023-11-20
LocalStack build git hash: 3e32b438
```


### Anything else?

Thank you so much for your hard work.
self,
        context: RequestContext,
        map_run_arn: LongArn,
        max_concurrency: MaxConcurrency = None,
        tolerated_failure_percentage: ToleratedFailurePercentage = None,
        tolerated_failure_count: ToleratedFailureCount = None,
    ) -> UpdateMapRunOutput:
        if tolerated_failure_percentage is not None or tolerated_failure_count is not None:
            raise NotImplementedError(
                "Updating of ToleratedFailureCount and ToleratedFailurePercentage is currently unsupported."
            )
        # 
        store = self.get_store(context)
        for execution in store.executions.values():
            map_run_record: Optional[
                MapRunRecord
            ] = execution.exec_worker.env.map_run_record_pool_manager.get(map_run_arn)
            if map_run_record is not None:
                map_run_record.update(
                    max_concurrency=max_concurrency,
                    tolerated_failure_count=tolerated_failure_count,
                    tolerated_failure_percentage=tolerated_failure_percentage,
                )
                LOG.warning(
                    "StepFunctions UpdateMapRun changes are currently not being reflected in the MapRun instances."
                )
                return UpdateMapRunOutput()
        raise ResourceNotFound()