added unit tests for validate_subscriptions

gso/schedules/validate_subscriptions.py

@@ -13,7 +13,12 @@ logger = structlog.get_logger(__name__)
 @celery.task
 @scheduler(name="Subscriptions Validator", minute="10", hour="0")
 def validate_subscriptions() -> None:
-    for subscription in get_insync_subscriptions():
+    subscriptions = get_insync_subscriptions()
+    if not subscriptions:
+        logger.info("No subscriptions to validate")
+        return
+
+    for subscription in subscriptions:
         validation_workflow = None
 
         for workflow in subscription.product.workflows: