fix: detect hidden_by_limit

closes 101

slack_cleaner2/model.py

@@ -686,7 +686,7 @@ def __init__(self, entry: JSONDict, slack: "SlackCleaner"):
         :type slack: SlackCleaner
         """
         self.id = entry["id"]
-        self.hidden_by_limit = "hidden_by_limit" in entry
+        self.hidden_by_limit = "hidden_by_limit" in entry or entry.get("mode", "") == "hidden_by_limit"
         self.name = entry.get("name", "Unknown")
         self.title = entry.get("title", "Unknown")
         self.pinned_to = entry.get("pinned_to", False)
@@ -698,11 +698,13 @@ def __init__(self, entry: JSONDict, slack: "SlackCleaner"):
         self._slack = slack
 
     @cached_property
-    def user(self) -> SlackUser:
+    def user(self) -> Optional[SlackUser]:
         """
         user created this file
         """
-        return self._slack.users.resolve_user(self.json["user"])
+        if "user" in self.json:
+            return self._slack.users.resolve_user(self.json["user"])
+        return None
 
     @staticmethod
     def list(