Fix test to expect defer: true for default loading strategy

The default loading strategy was changed to :defer (from :async) to prevent
race conditions. The test was incorrectly still expecting async behavior
when async is supported.

Now correctly expects { defer: true } for the default behavior, which
matches the configuration change in commit 4faf810.

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

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

spec/dummy/spec/helpers/react_on_rails_helper_spec.rb

@@ -77,14 +77,9 @@ def self.pro_attribution_comment
       allow(helper).to receive(:append_stylesheet_pack_tag)
       expect { helper.load_pack_for_generated_component("component_name", render_options) }.not_to raise_error
 
-      # Expect the default loading strategy based on Shakapacker version
-      if ReactOnRails::PackerUtils.supports_async_loading?
-        expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name",
-                                                                          { defer: false, async: true })
-      else
-        # When async is not supported, defaults to :defer which means { defer: true }
-        expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name", { defer: true })
-      end
+      # Default loading strategy is now always :defer to prevent race conditions
+      # between component registration and hydration, regardless of async support
+      expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name", { defer: true })
       expect(helper).to have_received(:append_stylesheet_pack_tag).with("generated/component_name")
     end