Enable SERVICE_MANAGED permission model StackSets to deploy stack instances in management account

### Name of the resource

AWS::CloudFormation::StackSet

### Resource name

StackSets (Service Managed Permission Model)

### Description

Currently, Service Managed StackSets doesn't deploy stack instances to the organization's management account, even if the management account is in your organization or in an OU in your organization.
This is a feature request to support the option to be able to deploy into all accounts within the Organization or OU, including the management account when using Service Managed permission model (including Automatic Deployment option).

### Other Details

https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/stacksets-getting-started-create.html?icmpid=docs_cfn_console#stacksets-orgs-associate-stackset-with-org

Start with the linked AWS CloudFormation StackSets documentation and review the service-managed permission model, including automatic deployment. Done means StackSet instances can be deployed to the organization's management account when targeting the organization or an OU.

Written by the indexing model from the issue text.