chore: remove specific settings for firefox extension

Author: webfansplz

packages/firefox-extension/manifest.json

@@ -14,12 +14,6 @@
     "default_popup": "popups/not-found.html",
     "default_title": "Vue DevTools"
   },
-  "browser_specific_settings": {
-    "gecko": {
-      "id": "@vue-devtools",
-      "strict_min_version": "58.0"
-    }
-  },
   "content_scripts": [
     {
       "js": [