### 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, state_machine_version_arn: LongArn
    ) -> DeleteStateMachineVersionOutput:
        state_machines = self.get_store(context).state_machines
        state_machine_version = state_machines.get(state_machine_version_arn)
        if isinstance(state_machine_version, StateMachineVersion):
            state_machines.pop(state_machine_version.arn)
            state_machine_revision = state_machines.get(state_machine_version.source_arn)
            if isinstance(state_machine_revision, StateMachineRevision):
                state_machine_revision.delete_version(state_machine_version_arn)
        return DeleteStateMachineVersionOutput()
    def stop_execution(
        self,
        context: RequestContext,
        execution_arn: Arn,
        error: SensitiveError = None,
        cause: SensitiveCause = None,
    ) -> StopExecutionOutput:
        execution: Execution = self._get_execution(context=context, execution_arn=execution_arn)
        stop_date = datetime.datetime.now()
        execution.stop(stop_date=stop_date, cause=cause, error=error)
        return StopExecutionOutput(stopDate=stop_date)
    def update_state_machine(
        self,
        context: RequestContext,
        state_machine_arn: Arn,
        definition: Definition = None,
        role_arn: Arn = None,
        logging_configuration: LoggingConfiguration = None,
        tracing_configuration: TracingConfiguration = None,