饼图显示问题，中间有一条细线echarts 配置项内容和展示

      app.title = '环形图';

option = {
    tooltip: {
        trigger: 'item',
        formatter: "{a} <br/>{b}: {c} ({d}%)"
    },
    legend: {
        orient: 'vertical',
        x: 'left',
        data:['直接访问','邮件营销','联盟广告','视频广告','搜索引擎','搜索引擎1','搜索引擎2']
    },
    series: [
        {
            "type":"pie",
        "radius":["10%","35%"],
        "data":[
            {"value":23011,"name":"直接访问"},
            {"value":8303,"name":"邮件营销"},
            {"value":7355,"name":"联盟广告"},
            {"value":2966,"name":"视频广告"},
            {"value":2619,"name":"搜索引擎"},
            {"value":25,"name":"搜索引擎1"},
            {"value":16,"name":"搜索引擎2"},
        ],
        "label":{
            "normal":{
                "position":"outside",
                "formatter":"{b}\n{d}%"
                
            }
            
        },
        }
    ]
};