### 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.
_next_version_number: int
    versions: Final[dict[RevisionId, Arn]]
    tag_manager: Final[TagManager]
    def __init__(
        self,
        name: Name,
        arn: Arn,
        definition: Definition,
        role_arn: Arn,
        create_date: Optional[datetime] = None,
        sm_type: Optional[StateMachineType] = None,
        logging_config: Optional[LoggingConfiguration] = None,
        tags: Optional[TagList] = None,
        tracing_config: Optional[TracingConfiguration] = None,
    ):
        super().__init__(
            name,
            arn,
            definition,
            role_arn,
            create_date,
            sm_type,
            logging_config,
            tags,
            tracing_config,
        )
        self.versions = dict()
        self._version_number = 0
        self.tag_manager = TagManager()
    def create_revision(