streams: Fix setting values passed in never subbed dicts.

This commit fixes the code to pass AnonymousSettingGroupDict
value instead of group ID when the setting is set to anonymous
groups in never subscribred streams subscription dicts.

zerver/lib/types.py

@@ -220,7 +220,7 @@ class SubscriptionStreamDict(TypedDict):
 
 class NeverSubscribedStreamDict(TypedDict):
     is_archived: bool
-    can_remove_subscribers_group: int
+    can_remove_subscribers_group: int | AnonymousSettingGroupDict
     creator_id: int | None
     date_created: int
     description: str