Component: Use full save to update alerts

We want to update the timestamp as well.

weblate/trans/models/component.py

@@ -1603,7 +1603,7 @@ def add_alert(self, alert, **details):
 
         if not created:
             obj.details = details
-            obj.save(update_fields=["details"])
+            obj.save()
         if ALERTS[alert].link_wide:
             for component in self.linked_childs:
                 component.add_alert(alert, **details)