Fix Sticker.set_name being treated as tuple/list-like when should in fact be a string

Yes, that little comma messed things up (again)

pyrogram/client/types/messages_and_media/sticker.py

@@ -94,7 +94,7 @@ class Sticker(Object):
         self.width = width
         self.height = height
         self.emoji = emoji
-        self.set_name = set_name,
+        self.set_name = set_name
         self.thumbs = thumbs
         # self.mask_position = mask_position