[Bug Report] Using Dart-Sass with element-ui libraries has an icon garbled problem

### What is Expected?
The Element-ui source code was developed using node-sass, but the project had requirements for Dart-Sass.
When running online, there will occasionally be garbled icon codes.
Although the solution is obtained by searching on the Internet: by using css-unicode-loader, the double-byte characters in the dart-sass compiled into css files are then converted back to the hexadecimal code.
But it is hoped that this problem will be solved at the root.

Technology stack：Vue、Element-ui、Dart-Sass