Removed dependency on plugin-webperf-core

Author: 7h3Rabbit

package.json

@@ -50,7 +50,6 @@
     "jsdom": "26.0.0",
     "eslint": "9.23.0",
     "globals": "16.0.0",
-    "plugin-webperf-core": "2025.3.8",
     "@sitespeed.io/log": "0.2.6",
     "@sitespeed.io/plugin": "1.0.0"
   },