### Is there an existing issue for this?

- [X] I have searched the existing issues

### Current Behavior

When attempting to list roles where permission boundaries are attached the response cannot be serialized 

`aws --endpoint-url=http://localhost:4566 iam list-roles --region ap-southeast-2`
```
An error occurred (InternalError) when calling the ListRoles operation (reached max retries: 2): exception while calling iam.ListRoles: Invalid type when serializing AttachedPermissionsBoundary: '<Element 'member' at 0xffff8275ef20>' cannot be parsed to structure.
```

### Expected Behavior

Expect that all roles are listed

### How are you starting LocalStack?

With a docker-compose file

### Steps To Reproduce

#### How are you starting localstack (e.g., `bin/localstack` command, arguments, or `docker-compose.yml`)

    docker run localstack/localstack

#### Client commands (e.g., AWS SDK code snippet, or sequence of "awslocal" commands)

* Create an IAM policy
* Create an IAM role which used the policy as a permission boundary
* Attempt to list all roles with `aws --endpoint-url=http://localhost:4566 iam list-roles --region ap-southeast-2`


### Environment

```markdown
- OS: MacOS
- LocalStack: latest
```


### Anything else?

_No response_
self,
        context: RequestContext,
        group_name: groupNameType,
        new_path: pathType = None,
        new_group_name: groupNameType = None,
    ) -> None:
        new_group_name = new_group_name or group_name
        backend = get_iam_backend(context)
        group = backend.get_group(group_name)
        group.path = new_path
        group.name = new_group_name
        backend.groups[new_group_name] = backend.groups.pop(group_name)
    def list_instance_profile_tags(
        self,
        context: RequestContext,
        instance_profile_name: instanceProfileNameType,
        marker: markerType = None,
        max_items: maxItemsType = None,
    ) -> ListInstanceProfileTagsResponse:
        backend = get_iam_backend(context)
        profile = backend.get_instance_profile(instance_profile_name)
        response = ListInstanceProfileTagsResponse()
        response["Tags"] = [Tag(Key=k, Value=v) for k, v in profile.tags.items()]
        return response
    def tag_instance_profile(