Refactor JavaScript pack tag expectations in ReactOnRailsHelper spec

- Simplified the expectation for the JavaScript pack tag in the ReactOnRailsHelper spec by removing conditional checks based on the CI_PACKER_VERSION environment variable.
- This change enhances the clarity of the test and ensures consistent behavior across different environments.

Author: AbanoubGhadban

spec/dummy/spec/helpers/react_on_rails_helper_spec.rb

@@ -64,12 +64,7 @@ class PlainReactOnRailsHelper
       allow(helper).to receive(:append_stylesheet_pack_tag)
       expect { helper.load_pack_for_generated_component("component_name", render_options) }.not_to raise_error
 
-      if ENV["CI_PACKER_VERSION"] == "oldest"
-        expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name", { defer: false })
-      else
-        expect(helper).to have_received(:append_javascript_pack_tag)
-          .with("generated/component_name", { defer: false, async: true })
-      end
+      expect(helper).to have_received(:append_javascript_pack_tag).with("generated/component_name", { defer: false })
       expect(helper).to have_received(:append_stylesheet_pack_tag).with("generated/component_name")
     end