错误代码修正，修改引用信息

src/server/models/sessions/sessions.js

@@ -480,7 +480,7 @@ class Sessions extends RedisModel {
        let participants = new Participants();
        let sessionKey = RedisModel.makeRedisKey(REDIS_KEYS.Session, sessionId);
        let messageId = mongoose.Types.ObjectId().toString();
        message.message_id = messageId;
        // 检查会话中是否存在此成员
        participants.existsParticipant(sessionId, message.sender_id, function (err, res) {
            if (err) {
@@ -527,6 +527,7 @@ class Sessions extends RedisModel {
        let participants = new Participants();
        let session_key = RedisModel.makeRedisKey(REDIS_KEYS.Session, sessionId);
        let messageId = mongoose.Types.ObjectId().toString();
        message.message_id = messageId;
        let sessionType = 0;
        let name = "";
        participants.existsParticipant(sessionId, message.senderId, function (err, res) {