### 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.
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        state_machines = self.get_store(context).state_machines
        if not name and arn in state_machines:
            raise InvalidName()
        state_machine = StateMachineRevision(
            name=name,
            arn=arn,
            role_arn=request["roleArn"],
            definition=request["definition"],
            sm_type=request.get("type"),
            logging_config=request.get("loggingConfiguration"),
            tags=request.get("tags"),
            tracing_config=request.get("tracingConfiguration"),
        )
        tags = request.get("tags")
        if tags:
            state_machine.tag_manager.add_all(tags)
        state_machines[arn] = state_machine
        create_output = CreateStateMachineOutput(
            stateMachineArn=state_machine.arn, creationDate=state_machine.create_date
        )
        if request.get("publish", False):
            version_description = request.get("versionDescription")
            state_machine_version = state_machine.create_version(description=version_description)
            if state_machine_version is not None:
                state_machine_version_arn = state_machine_version.arn
                state_machines[state_machine_version_arn] = state_machine_version
                create_output["stateMachineVersionArn"] = state_machine_version_arn
        return create_output
    def describe_state_machine(