Fix pre php8 function signatures

CRM/Core/Payment/StripeCheckout.php

@@ -157,8 +157,10 @@ class CRM_Core_Payment_StripeCheckout extends CRM_Core_Payment_Stripe {
 
   /**
    * This gathers the line items which are then used in buildCheckoutLineItems()
+   *
+   * @param array|PropertyBag $paymentParams
    */
-  public function calculateLineItems(array|PropertyBag $paymentParams): array {
+  public function calculateLineItems($paymentParams): array {
     $lineItems = [];
     if (!empty($paymentParams['skipLineItem']) || empty($paymentParams['line_item'])) {
       if (!empty($paymentParams['participants_info'])) {