refactor(PosterBuilder): 使用getWindowInfo替代getSystemInfoSync获取屏幕宽度

getSystemInfoSync已被弃用，改用推荐的getWindowInfo方法获取窗口信息

@@ -102,7 +102,7 @@ export function mapHttpToHttps(rawUrl) {
  * @returns { number } factor 单位转换系数 1rpx = factor * px
  */
 export const getFactor = () => {
-  const sysInfo = Taro.getSystemInfoSync();
+  const sysInfo = Taro.getWindowInfo();
   const { screenWidth } = sysInfo;
   return screenWidth / 750;
 };