Fix undefined organization variable in by_item_id spec

Remove explicit organization: parameter from factory calls in the
by_item_id scope test. The organization variable is not defined in
this scope, causing a NameError. The factory defaults handle
organization assignment correctly, matching the pattern used by
other scope tests in this file. Also removes extra blank line
flagged by Rubocop.

Author: costajohnt

spec/models/donation_spec.rb

@@ -159,14 +159,13 @@
 
     describe "by_item_id >" do
       it "returns only donations with the specified item" do
-        item1 = create(:item, organization: organization)
-        item2 = create(:item, organization: organization)
-        create(:donation, :with_items, item: item1, organization: organization)
-        create(:donation, :with_items, item: item2, organization: organization)
+        item1 = create(:item)
+        item2 = create(:item)
+        create(:donation, :with_items, item: item1)
+        create(:donation, :with_items, item: item2)
         expect(Donation.by_item_id(item1.id).count).to eq(1)
       end
     end
-
   end
 
   context "Associations >" do