update zh-cn/application-dev/reference/apis/js-apis-screen.md：自动化测试问题修改，需同步翻译

Signed-off-by: Nge-yafang <geyafang@huawei.com>

zh-cn/application-dev/reference/apis/js-apis-screen.md

@@ -55,7 +55,7 @@ getAllScreens(): Promise<Array<Screen>>
 **示例：**
 ```js
 var screenClass = null;
-let promise = screen.getAllScreen();
+let promise = screen.getAllScreens();
 promise.then((data) => {
     screenClass = data[0];
     console.log('Succeeded in getting all screens . Data:'+ JSON.stringify(data));