fix: incorrect attribute name in system MI helper example (#771)

Author: kewalaka

docs/static/includes/interfaces/int.mi.schema.tf

@@ -20,7 +20,7 @@ locals {
   managed_identities = {
     system_assigned_user_assigned = (var.managed_identities.system_assigned || length(var.managed_identities.user_assigned_resource_ids) > 0) ? {
       this = {
-        type                       = var.managed_identities.value.system_assigned && length(var.managed_identities.user_assigned_resource_ids) > 0 ? "SystemAssigned, UserAssigned" : length(var.managed_identities.user_assigned_resource_ids) > 0 ? "UserAssigned" : "SystemAssigned"
+        type                       = var.managed_identities.system_assigned && length(var.managed_identities.user_assigned_resource_ids) > 0 ? "SystemAssigned, UserAssigned" : length(var.managed_identities.user_assigned_resource_ids) > 0 ? "UserAssigned" : "SystemAssigned"
         user_assigned_resource_ids = var.managed_identities.user_assigned_resource_ids
       }
     } : {}