@types/payment Add formatCardNumber in the types (#28669)

I wanna use the `formatCardNumber` function standalone but it is not defined in the types yet, so there we go.

types/payment/index.d.ts

@@ -11,6 +11,10 @@ interface Fns {
      * * Validates length
      */
     validateCardNumber(cardNumber: string): boolean;
+    /**
+     * Formats a card number
+     */
+    formatCardNumber(cardNumber: string): string;
     /**
      * Validates a card expiry:
      * * Validates numbers