test(cypress): use createConfirmPaymentTest in 50/50 volume routing test
Replace raw cy.request block in payment-routing-test-1 with cy.createConfirmPaymentTest
pattern, matching the style used in 100% stripe and 100% adyen contexts.
Explicitly set connectorId/merchantConnectorId for both payment-1 (stripe) and
payment-2 (adyen) instead of relying on non-deterministic response capture.
Co-Authored-By: Paperclip <noreply@paperclip.ing>