ci: enable CORS in wpt run

.github/workflows/wpt.yml

@@ -113,7 +113,7 @@ jobs:
         run: |
           ./wpt serve 2> /dev/null & echo $! > WPT.pid
           sleep 20s
-          ./wptrunner -lpd-path ./lightpanda -json -concurrency 8 -pool 4 --mem-limit 200 > wpt.json
+          ./wptrunner -lpd-path ./lightpanda --experimental-features cors -json -concurrency 8 -pool 4 --mem-limit 200 > wpt.json
           kill `cat WPT.pid`
 
       - name: write commit