Handle new Defender managed assignments (#973)

* Handle new Defender managed assignments 

Adding a new case to skip Defender Plan Managed policies.
Azure Defender for Cloud is creating new assignments for "Defender for SQL servers on Machines provisioning" that do not follow the expected description naming convention "This policy assignment was automatically created by"... so EPAC is trying to delete them.

* change from full string to starts with

Made the new entry a little more generic

Author: sdecker

Scripts/Helpers/Confirm-PacOwner.ps1

@@ -32,7 +32,9 @@ function Confirm-PacOwner {
                         $ManagedByCounters.dfcSecurityPolicies += 1
                         return "managedByDfcSecurityPolicies"
                     }
-                    elseif ($description.StartsWith("This policy assignment was automatically created by ")) {
+                    elseif ($description.StartsWith("This policy assignment was automatically created by ") -or 
+                        $description.StartsWith("This initiative enables Defender ")
+                    ) {
                         $ManagedByCounters.dfcDefenderPlans += 1
                         return "managedByDfcDefenderPlans"
                     }