### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

I'm trying to create a state machine using the following definition that I validated on AWS:

```json
{
  "StartAt": "SetupVariables",
  "States": {
    "SetupVariables": {
      "Type": "Pass",
      "Parameters": {
        "items": []
      },
      "Next": "Map"
    },
    "Map": {
      "Type": "Map",
      "ItemsPath": "$.items",
      "ItemProcessor": {
        "StartAt": "Pass",
        "States": {
          "Pass": {
            "Type": "Pass",
            "End": true
          }
        }
      },
      "End": true
    }
  }
}
```

I get the following error:

```
│ Error: updating Step Functions State Machine (arn:aws:states:eu-west-3:000000000000:stateMachine:my-state-machine): InvalidDefinition: Error=ValueError Args=['Expected a ProcessorConfig declaration at \'"ItemProcessor":{"StartAt":"Pass","States":{"Pass":{"Type":"Pass","End":true}}}\'.'] in definition '{
│   "StartAt": "SetupVariables",
│   "States": {
│     "SetupVariables": {
│       "Type": "Pass",
│       "Parameters": {
│         "items": []
│       },
│       "Next": "Map"
│     },
│     "Map": {
│       "Type": "Map",
│       "ItemsPath": "$.items",
│       "ItemProcessor": {
│         "StartAt": "Pass",
│         "States": {
│           "Pass": {
│             "Type": "Pass",
│             "End": true
│           }
│         }
│       },
│       "End": true
│     }
│   }
│ }
│ '.
│ 
│   with aws_sfn_state_machine.main,
│   on stepFunction.tf line 1, in resource "aws_sfn_state_machine" "main":
│    1: resource "aws_sfn_state_machine" "main" {
```

On AWS the ProcessorConfig field is optional.
[The AWS documentation](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-asl-use-map-state-inline.html) specifies that this field is optional and provides [an example omitting it](https://docs.aws.amazon.com/step-functions/latest/dg/concepts-asl-use-map-state-inline.html#inline-map-state-example-params).
When using the AWS workflow editor I get an error saying "Map (ItemProcessor.ProcessorConfig): Value is mandatory."  but the creation still succeeds.

### Expected Behavior

The definition should be considered valid and the state machine should be created.

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

Create a state machine using the provided definition.

### Environment

```markdown
- LocalStack: 3.0.3.dev20231207105008
```


### Anything else?

_No response_
csv_headers: list[str] = list()
        for child in ctx.children[3:-1]:
            maybe_str = Antlr4Utils.is_production(
                pt=child, rule_index=ASLParser.RULE_keyword_or_string
            )
            if maybe_str is not None:
                csv_headers.append(self._inner_string_of(maybe_str))
        
        return CSVHeaders(header_names=csv_headers)
    def visitMax_items_path_decl(self, ctx: ASLParser.Max_items_path_declContext) -> MaxItemsPath:
        path: str = self._inner_string_of(parse_tree=ctx.STRINGPATH())
        return MaxItemsPath(path=path)
    def visitMax_items_decl(self, ctx: ASLParser.Max_items_declContext) -> MaxItems:
        return MaxItems(max_items=int(ctx.INT().getText()))
    def visitRetry_decl(self, ctx: ASLParser.Retry_declContext) -> RetryDecl:
        retriers: list[RetrierDecl] = list()
        for child in ctx.children:
            cmp: Optional[Component] = self.visit(child)
            if isinstance(cmp, RetrierDecl):
                retriers.append(cmp)
        return RetryDecl(retriers=retriers)
    def visitRetrier_decl(self, ctx: ASLParser.Retrier_declContext) -> RetrierDecl:
        props = RetrierProps()
        for child in ctx.children:
            cmp: Optional[Component] = self.visit(child)
            props.add(cmp)
        return RetrierDecl.from_retrier_props(props=props)
    def visitRetrier_stmt(self, ctx: ASLParser.Retrier_stmtContext):