CLDC-4325: Fix sales log spec in 2025

need to use let rather than let! so the timecop can run first

spec/models/sales_log_spec.rb

@@ -684,7 +684,7 @@ RSpec.describe SalesLog, type: :model do
   end
 
   context "when deriving household variables" do
-    let!(:sales_log) do
+    let(:sales_log) do
       create(
         :sales_log,
         :completed,
@@ -712,6 +712,15 @@ RSpec.describe SalesLog, type: :model do
       )
     end
 
+    before do
+      Timecop.travel(saledate)
+      Singleton.__init__(FormHandler)
+    end
+
+    after do
+      Timecop.return
+    end
+
     context "when 2025", metadata: { year: 25 } do
       let(:saledate) { collection_start_date_for_year(2025) }
       let(:hholdcount) { 4 }