add a test to ensure that the form handler does not add outdated forms to the forms hash with key nil

spec/models/form_handler_spec.rb

@@ -35,6 +35,23 @@ RSpec.describe FormHandler do
       expect(all_forms.count).to be >= 1
       expect(all_forms["current_sales"]).to be_a(Form)
     end
+
+    context "when in 23/24 period or later" do
+      let(:now) { Time.utc(2023, 6, 7) }
+
+      around do |example|
+        Timecop.freeze(now) do
+          Singleton.__init__(described_class)
+          example.run
+        end
+        Singleton.__init__(described_class)
+      end
+
+      it "does not load outdated forms" do
+        all_forms = form_handler.forms
+        expect(all_forms.keys).not_to include nil
+      end
+    end
   end
 
   describe "Get specific form" do