### 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_
non_existent_policy_arn = "arn:aws:iam::000000000000:policy/non-existent-policy"
        with pytest.raises(ClientError) as ctx:
            aws_client.iam.delete_policy(PolicyArn=non_existent_policy_arn)
        assert ctx.typename == "NoSuchEntityException"
        assert ctx.value.response["Error"]["Code"] == "NoSuchEntity"
    def test_recreate_iam_role(self, aws_client):
        role_name = "role-{}".format(short_uid())
        assume_policy_document = {
            "Version": "2012-10-17",
            "Statement": [
                {
                    "Action": "sts:AssumeRole",
                    "Principal": {"Service": "lambda.amazonaws.com"},
                }
            ],
        }
        rs = aws_client.iam.create_role(