fix: #8059, properly mark topic unread when using mark unread for all

src/socket.io/topics/unread.js

@@ -67,6 +67,7 @@ module.exports = function (SocketTopics) {
 			await topics.markAsUnreadForAll(tid);
 			await topics.updateRecent(tid, now);
 			await db.sortedSetAdd('cid:' + topicData.cid + ':tids:lastposttime', now, tid);
+			await topics.setTopicField(tid, 'lastposttime', now);
 		}));
 		topics.pushUnreadCount(socket.uid);
 	};