HarmonyOS 使用expandSafeArea([SafeAreaType.SYSTEM], [SafeAreaEdge.TOP])后，背景图片显示不完整，背景色能显示完整

需要在EntryAbility中设置窗口全屏，代码如下：

onWindowStageCreate(windowStage: window.WindowStage): void {
  windowStage.loadContent('pages/Index', (err, data) => {
  if (err.code) {
  return;
}
let windowClass: window.Window = windowStage.getMainWindowSync(); // 获取应用主窗口
// 1. 设置窗口全屏
let isLayoutFullScreen = true;
windowClass.setWindowLayoutFullScreen(isLayoutFullScreen)
  .then(() => {
    console.info('Succeeded in setting the window layout to full-screen mode.');
  })
  .catch((err: BusinessError) => {
    console.error('Failed to set the window layout to full-screen mode. Cause:' + JSON.stringify(err));
  });
});
}

参考指南：https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkts-develop-apply-immersive-effects-V5#section171801550301