don't use measure fields as color field and don't add it to xField in spec

[da730]

dataset: [ { "year": 2013, "GDP": 593000 }, { "year": 2022, "GDP": 1210000 }, { "year": 2013, "GDPPerCapita": 43497 }, { "year": 2022, "GDPPerCapita": 85698 } ]

prompt: 请绘制一个折线图，展示2013年至2022年中国的GDP和人均GDP的变化情况