Support for parallel region concurrency preference (RegionConcurrencyType=PARALLEL) for SERVICE-MANAGED AutoDeployment triggered deployments

### Name of the resource

Other

### Resource name

CloudFormation Stack Sets

### Description

When using an AutoDeployment model in a stack-set with SERVICE-MANAGED permissions, when a new account is added to the organization, the new operation created by AutoDeployment doesn't have a StackSet Operation Preferences.
In this case, when a new account gets added to the OU and the deployment starts automatically, the operation seems to only deploy to one region at a time.

As a fix, do add the option to set operation preferences such as RegionConcurrencyType=PARALLEL

### Other Details

NA

Start with the CloudFormation Stack Sets AutoDeployment behavior described here, focusing on SERVICE-MANAGED permissions and newly added organization accounts. Review how StackSet Operation Preferences are applied to automatically created operations, especially RegionConcurrencyType=PARALLEL. Done means those deployments honor the configured parallel region preference.

Written by the indexing model from the issue text.