Fix incorrect parsing of None

frigate/events/maintainer.py

@@ -163,6 +163,7 @@ class EventProcessor(threading.Thread):
                 )
             )
 
+            try:
                 attributes = [
                     (
                         None
@@ -179,6 +180,10 @@ class EventProcessor(threading.Thread):
                     )
                     for a in event_data["snapshot"]["attributes"]
                 ]
+            except TypeError:
+                logger.warning(
+                    f"Failed to parse attributes of event data, event data is {event_data}"
+                )
 
             # keep these from being set back to false because the event
             # may have started while recordings and snapshots were enabled