fix(deps): update dependency nodebb-plugin-mentions to v3 (#9966)

Co-authored-by: Renovate Bot <bot@renovateapp.com>

install/package.json

@@ -89,7 +89,7 @@
         "nodebb-plugin-emoji": "^3.5.0",
         "nodebb-plugin-emoji-android": "2.0.5",
         "nodebb-plugin-markdown": "8.14.4",
-        "nodebb-plugin-mentions": "2.15.2",
+        "nodebb-plugin-mentions": "3.0.0",
         "nodebb-plugin-spam-be-gone": "0.7.10",
         "nodebb-rewards-essentials": "0.2.0",
         "nodebb-theme-lavender": "5.2.1",