【报Bug】在3.6.17和3.6.18版本上APP使用MQTT连接不上

示例代码：

<template>  
    <view class="page-main">  
        <button type="default" @click="publish()" v-if="connected">发布MQTT消息</button>  
        <button type="default" @click="connectMqtt()" v-else>连接MQTT</button>  
    </view>  
</template>  

<script>  
    let mqtt = require('../../lib/mqtt.min.js')  
    export default {  
        data() {  
            return {  
                client: null,  
                connected: false,  
                testTopic: 'myTopic', //作为测试订阅的主题  
            };  
        },  
        methods: {  
            connectMqtt() {  
                uni.showLoading({  
                    title: '正在连接',  
                    mask: true  
                })  
                let username = uni.getSystemInfoSync().deviceId;  
                let password = uni.getSystemInfoSync().deviceId;  
                this.client = mqtt.connect(`wx://api.easylink.io/mqtt`, {  
                    port: 1983,  
                    keepalive: 10,  
                    protocolId: 'MQTT',  
                    protocolVersion: 4,  
                    connectTimeout: 5000,  
                    clientId: username,  
                    username: username,  
                    password: password,  
                });  
                // 监听MQTT连接成功回调  
                this.client.on('connect', (e) => {  
                    // MQTT服务链接成功  
                    console.log('MQTT连接成功==', e);  
                    uni.hideLoading();  
                    uni.showToast({  
                        title: '连接成功'  
                    })  
                    this.connected = true  
                    // 订阅一个主题topic用于测试  
                    this.client.subscribe(this.testTopic)  
                });  
                // 监听MQTT消息回调  
                this.client.on('message', (topic, payload) => {  
                    payload = payload.toString()  
                    console.log('收到自身订阅的测试主题消息==', payload);  
                    uni.showModal({  
                        title: '收到MQTT消息',  
                        content: payload,  
                        showCancel: false  
                    })  
                });  
                // 监听MQTT重连回调  
                this.client.on('reconnect', (e) => {  
                    uni.hideLoading()  
                    uni.showLoading({  
                        title: '正在连接',  
                        mask: true  
                    })  
                    this.connected = false  
                    console.log('[Mqtt]=> Reconnect:', e);  
                });  
                // 监听MQTT离线回调  
                this.client.on('offline', (e) => {  
                    uni.hideLoading();  
                    this.connected = false  
                    console.log('[Mqtt]=> Offline:', e);  
                });  
            },  
            publish() {  
                let payload = new Date().toLocaleString() //发布的MQTT消息  
                this.client.publish(this.testTopic, payload)  
            }  
        }  
    };  
</script>

操作步骤：

在3.6.18版本中运行实例demo到手机上，点击“连接MQTT”，此时无法连接成功。退回3.6.15版本重新运行实例demo,mqtt正常连接并能正常发布MQTT消息

预期结果：

在最新版本HBuilderX上能正常连接MQTT

实际结果：

在最新版本HBuilderX上无法正常连接MQTT