Bug? CloudFromation AWS::ServiceCatalog::PortfolioPrincipalAssociation does not delete IAM_PATTERN principals

Bug: CloudFormation resource AWS::ServiceCatalog::PortfolioPrincipalAssociation allows for creating resources with type IAM_PATTERN, even though the documentation does not allow the. Those resources always fail to be deleted.

Excepted behavior:

• Resource fails validation during creation, or
• Resource can be deleted

To replicate: Deploy this template. Delete it.

{
 "Resources": {
  "Portfolio": {
   "Type": "AWS::ServiceCatalog::Portfolio",
   "Properties": {
    "DisplayName": "test",
    "ProviderName": "test",
    "Description": "test"
   },
   "PrincipalAssoc": {
    "Type": "AWS::ServiceCatalog::PortfolioPrincipalAssociation",
    "Properties": {
     "PortfolioId": {
      "Ref": "Portfolio"
     },
     "PrincipalARN": "arn:aws:iam:::role/SomeRolePattern*",
     "PrincipalType": "IAM_PATTERN"
    }
   }
  }
 }
}