Fix webpack assets status checker test compatibility

Use generated_assets_full_path instead of public_bundles_full_path in
non-packer bundle resolution to maintain test compatibility. Tests mock
the deprecated method name for backwards compatibility.

This fixes CI failures in webpack_assets_status_checker_spec.rb while
maintaining the new server bundle security features.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

Author: justin808

lib/react_on_rails/utils.rb

@@ -103,7 +103,7 @@ def self.bundle_js_file_path(bundle_name)
         # Default to the non-hashed name in the specified output directory, which, for legacy
         # React on Rails, this is the output directory picked up by the asset pipeline.
         # For Shakapacker, this is the public output path defined in the (shaka/web)packer.yml file.
-        File.join(public_bundles_full_path, bundle_name)
+        File.join(generated_assets_full_path, bundle_name)
       end
     end