Add progressive enhancement JS for active_language

spec/helpers/active_language_helper_spec.rb

@@ -25,7 +25,10 @@ RSpec.describe ActiveLanguageHelper, type: :helper do
 
     it "should not contain an English option" do
       expect(@tag).to_not include("English")
-      
+    end
+
+    it "should include css id #active_language_select_tag" do
+      expect(@tag).to have_selector(%(select[id="active_language_select_tag"]))
     end
   end
 end