fix(configprovider): css import path error

Author: Miles-hxy

src/sites/sites-react/doc/docs/react/start-react.en-US.md

@@ -53,7 +53,7 @@ import Button from '@nutui/nutui-react/dist/es/packages/button'
 It is important to note that when manually loading components on demand, you also need to import the global class file in your entry file to load some of NutUI React's global logic and styles:
 
 ```js
-import '@nutui/nutui-react/dist/styles/themes/default.scss'
+import '@nutui/nutui-react/dist/styles/themes/default.css'
 ```
 
 #### Method 3: Automatic On-Demand Loading

src/sites/sites-react/doc/docs/react/start-react.md

@@ -53,7 +53,7 @@ import Button from '@nutui/nutui-react/dist/es/packages/button'
 需要注意的是，`在手动按需加载时，你还需要在入口文件中引入 global 类的文件来加载一些 NutUI React 的全局性逻辑和样式：`
 
 ```js
-import '@nutui/nutui-react/dist/styles/themes/default.scss'
+import '@nutui/nutui-react/dist/styles/themes/default.css'
 ```
 
 #### 方法三、自动的按需加载

src/sites/sites-react/doc/docs/taro/start-react.en-US.md

@@ -115,7 +115,7 @@ You can also implement on-demand import of styles in the following ways:
 Note that when manually loading components on demand, you also need to import the global class file in the entry file to load some of NutUI React Taro's global logic and styles:
 
 ```js
-import '@nutui/nutui-react-taro/dist/styles/themes/default.scss'
+import '@nutui/nutui-react-taro/dist/styles/themes/default.css'
 ```
 
 Install `babel-plugin-import`.

src/sites/sites-react/doc/docs/taro/start-react.md

@@ -118,7 +118,7 @@ import '@nutui/nutui-react-taro/dist/style.css'
 需要注意的是，`在手动按需加载时，你还需要在入口文件中引入 global 类的文件来加载一些 NutUI React Taro 的全局性逻辑和样式：`
 
 ```js
-import '@nutui/nutui-react-taro/dist/styles/themes/default.scss'
+import '@nutui/nutui-react-taro/dist/styles/themes/default.css'
 ```
 
 首先安装 `babel-plugin-import` 插件