Fix: overdue invoices should not include invoices not ready to be paid (#3315)

Together AI have an error when triggering
`DunningCampaigns::ProcessAttemptJob`:
`BaseService::MethodNotAllowedFailure:
invoices_not_ready_for_payment_processing`
this happens because when selecting overdue invoices, we do not filter
invoices that are ready for payment processing.

- Added filter invoices to be ready_to_be_processed when filtering
invoices for dunning_campaign process_attempt

Author: annvelents

app/services/dunning_campaigns/process_attempt_service.rb

@@ -72,6 +72,7 @@ def overdue_invoices
       customer
         .invoices
         .payment_overdue
+        .where(ready_for_payment_processing: true)
         .where(currency: dunning_campaign_threshold.currency)
     end
   end

spec/services/dunning_campaigns/process_attempt_service_spec.rb

@@ -171,6 +171,23 @@
           .and raise_error(BaseService::ServiceFailure)
       end
     end
+
+    context "when a customer has invoices that are not ready for payment processing" do
+      let(:invoice_5) { create :invoice, organization:, customer:, currency:, payment_overdue: true, ready_for_payment_processing: false, total_amount_cents: 99_00 }
+
+      before { invoice_5 }
+
+      it "creates payment only for ready_for_processing invoice" do
+        expect(result.payment_request).to eq payment_request
+        expect(PaymentRequests::CreateService).to have_received(:call)
+          .with(organization:,
+            params: {
+              external_customer_id: customer.external_id,
+              lago_invoice_ids: [invoice_2.id]
+            },
+            dunning_campaign:)
+      end
+    end
   end
 
   it "does nothing" do