### 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,
        instance_profile_name: instanceProfileNameType,
        tags: tagListType,
    ) -> None:
        backend = get_iam_backend(context)
        profile = backend.get_instance_profile(instance_profile_name)
        value_by_key = {tag["Key"]: tag["Value"] for tag in tags}
        profile.tags.update(value_by_key)
    def untag_instance_profile(
        self,
        context: RequestContext,
        instance_profile_name: instanceProfileNameType,
        tag_keys: tagKeyListType,
    ) -> None:
        backend = get_iam_backend(context)
        profile = backend.get_instance_profile(instance_profile_name)
        for tag in tag_keys:
            profile.tags.pop(tag, None)
    def create_service_linked_role(