Unhandled exception occurs when postal code isnt provided

[JiyaadDolly]

We are seeing the following error when a postal code value isn't provided during a guest checkout.

report.CRITICAL: Exception: 
Deprecated Functionality: preg_replace(): Passing null to parameter #3 ($subject) of type array|string is deprecated in /app/vendor/realexpayments/hpp/Model/PaymentMethod.php on line 405

Expected Result on checkout:
The Payment widgets loads allowing the customer to pay

Actual Result:
The payment widget does not load, resulting in a blank payment option

Recommendation is to add the following:
Adjust the following code at realexpayments/hpp/Model/PaymentMethod.php from:

$postalBit = $order->getShippingAddress()->getPostcode();
            if ($shippingCountryCode == "GB") {

To:

$postalBit = $order->getShippingAddress()->getPostcode();
            if ($shippingCountryCode == "GB" && isset($postalBit)) {

Reference code:

ecommerce-magento-2/RealexPayments/HPP/Model/PaymentMethod.php

Lines 403 to 405 in fb1d5a0

	$postalBit = $order->getShippingAddress()->getPostcode();
	if ($shippingCountryCode == "GB") {
	$postalBit = preg_replace('/\D/', '', $postalBit);