Subreddit: remove unusable .flair property

The flair_ids() function is disabled, so this property did not work.

r2/r2/models/subreddit.py

@@ -573,10 +573,6 @@ class Subreddit(Thing, Printable, BaseSite):
     def subscribers(self):
         return self.subscriber_ids()
 
-    @property
-    def flair(self):
-        return self.flair_ids()
-
     @property
     def accounts_active(self):
         if self.hide_num_users_info: