### 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, request: CreateStateMachineInput
    ) -> CreateStateMachineOutput:
        if not request.get("publish", False) and request.get("versionDescription"):
            raise ValidationException("Version description can only be set when publish is true")
        
        # 
        idem_state_machine: Optional[StateMachineRevision] = self._idempotent_revision(
            context=context, request=request
        )
        if idem_state_machine is not None:
            return CreateStateMachineOutput(
                stateMachineArn=idem_state_machine.arn, creationDate=idem_state_machine.create_date
            )
        state_machine_with_name: Optional[StateMachineRevision] = self._revision_by_name(
            context=context, name=request["name"]
        )
        if state_machine_with_name is not None:
            raise StateMachineAlreadyExists(
                f"State Machine Already Exists: '{state_machine_with_name.arn}'"
            )
        state_machine_definition: str = request["definition"]
        StepFunctionsProvider._validate_definition(definition=state_machine_definition)
        name: Optional[Name] = request["name"]
        arn = stepfunctions_state_machine_arn(
            name=name, account_id=context.account_id, region_name=context.region