### 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
    ) -> DescribeMapRunOutput:
        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:
                return map_run_record.describe()
        raise ResourceNotFound()
    def list_map_runs(
        self,
        context: RequestContext,
        execution_arn: Arn,
        max_results: PageSize = None,
        next_token: PageToken = None,
    ) -> ListMapRunsOutput:
        # 
        execution = self._get_execution(context=context, execution_arn=execution_arn)
        map_run_records: list[
            MapRunRecord
        ] = execution.exec_worker.env.map_run_record_pool_manager.get_all()
        return ListMapRunsOutput(
            mapRuns=[map_run_record.list_item() for map_run_record in map_run_records]
        )
    def update_map_run(