### 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_
permissions_boundary="",
            description=description,
            tags={},
            max_session_duration=3600,
        )
        role.service_linked_role_arn = "arn:aws:iam::{0}:role/aws-service-role/{1}/{2}".format(
            context.account_id, aws_service_name, role.name
        )
        res_role = self.moto_role_to_role_type(role)
        return CreateServiceLinkedRoleResponse(Role=res_role)
    def delete_service_linked_role(
        self, context: RequestContext, role_name: roleNameType
    ) -> DeleteServiceLinkedRoleResponse:
        
        backend = get_iam_backend(context)
        backend.delete_role(role_name)
        return DeleteServiceLinkedRoleResponse(DeletionTaskId=short_uid())
    def get_service_linked_role_deletion_status(
        self, context: RequestContext, deletion_task_id: DeletionTaskIdType
    ) -> GetServiceLinkedRoleDeletionStatusResponse:
        
        return GetServiceLinkedRoleDeletionStatusResponse(Status=DeletionTaskStatusType.SUCCEEDED)
    def put_user_permissions_boundary(
        self, context: RequestContext, user_name: userNameType, permissions_boundary: arnType
    ) -> None:
        if user := get_iam_backend(context).users.get(user_name):
            user.permissions_boundary = permissions_boundary
        else:
            raise NoSuchEntityException()
    def delete_user_permissions_boundary(