UX: Hide tags section in sidebar when user has no visible tags (#18539)

Also hides the tags configuration for sidebar under user preferences

Internal ref: /t/73500

spec/serializers/current_user_serializer_spec.rb

@@ -387,4 +387,6 @@ RSpec.describe CurrentUserSerializer do
       expect(serializer.as_json[:associated_account_ids]).to eq({ "twitter" => "1" })
     end
   end
+
+  include_examples "#display_sidebar_tags", described_class
 end