fix client compiling error - replace node-sass w sass.

Author: James Fuqian

client/package.json

@@ -14,11 +14,11 @@
     "@types/react-dom": "^17.0.0",
     "axios": "^0.21.2",
     "http-proxy-middleware": "^1.3.1",
-    "node-sass": "^7.0.0",
     "react": "^17.0.2",
     "react-dom": "^17.0.2",
     "react-router-dom": "^5.2.0",
     "react-scripts": "4.0.3",
+    "sass": "^1.49.7",
     "typescript": "^4.1.2",
     "web-vitals": "^1.0.1"
   },