[vite-plugin-mercury] Add missing "sass" dependency (#681)

Author: ncamera

packages/mercury-build/package.json

@@ -20,7 +20,8 @@
   },
   "license": "Apache-2.0",
   "dependencies": {
-    "oxc-resolver": "~11.10.0"
+    "oxc-resolver": "~11.10.0",
+    "sass": "~1.86.3"
   },
   "devDependencies": {
     "@eslint/js": "*",