Never trust peers sticker set name in secret chats.

GitOrigin-RevId: 11f6534963920bd7c736a9cb3dcf3c73e2e68e6c

td/telegram/StickersManager.cpp

@@ -1868,7 +1868,9 @@ StickerSetId StickersManager::on_get_input_sticker_set(FileId sticker_file_id,
               }
             }));
       }
-      return set_id;
+      // always return empty StickerSetId, because we can't trust the set_id provided by the peer in the secret chat
+      // the real sticker set id will be set in on_get_sticker if and only if the sticker is really from the set
+      return StickerSetId();
     }
     case telegram_api::inputStickerSetAnimatedEmoji::ID:
       return add_special_sticker_set(SpecialStickerSetType(set_ptr).type_).id_;