### 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.
InvalidName,
    InvalidToken,
    ListExecutionsOutput,
    ListExecutionsPageToken,
    ListMapRunsOutput,
    ListStateMachinesOutput,
    ListStateMachineVersionsOutput,
    ListTagsForResourceOutput,
    LoggingConfiguration,
    LongArn,
    MaxConcurrency,
    MissingRequiredParameter,
    Name,
    PageSize,
    PageToken,
    Publish,
    PublishStateMachineVersionOutput,
    ResourceNotFound,
    ReverseOrder,
    RevisionId,
    SendTaskFailureOutput,
    SendTaskHeartbeatOutput,
    SendTaskSuccessOutput,
    SensitiveCause,
    SensitiveData,
    SensitiveError,
    StartExecutionOutput,
    StateMachineAlreadyExists,
    StateMachineDoesNotExist,
    StateMachineList,