correct linting problem and update tests to account for change in validation

app/models/validations/sales/financial_validations.rb

@@ -37,7 +37,7 @@ module Validations::Sales::FinancialValidations
   end
 
   def validate_mortgage(record)
-    record.errors.add :mortgage, I18n.t("validations.financial.mortgage") if record.mortgage_used? && record.mortgage == 0
+    record.errors.add :mortgage, I18n.t("validations.financial.mortgage") if record.mortgage_used? && record.mortgage&.zero?
   end
 
   def validate_cash_discount(record)

spec/models/validations/sales/financial_validations_spec.rb

@@ -117,12 +117,14 @@ RSpec.describe Validations::Sales::FinancialValidations do
     let(:record) { FactoryBot.create(:sales_log) }
 
     it "adds an error is the mortgage is zero" do
+      record.mortgageused = 1
       record.mortgage = 0
       financial_validator.validate_mortgage(record)
       expect(record.errors[:mortgage]).to include I18n.t("validations.financial.mortgage")
     end
 
     it "does not add an error is the mortgage is positive" do
+      record.mortgageused = 1
       record.mortgage = 234
       financial_validator.validate_mortgage(record)
       expect(record.errors).to be_empty