Update Customer class to allow nullable networkAddress and countryCod…

[OttiaDevsPT]

This update enhances the customer data handling logic by ensuring that the setNetworkAddress() and setCountryCode() methods are only executed when their respective properties are explicitly provided.

Changes Made:
Added conditional checks for $customer->network_address and $customer->country_code.
The setters are now called only if the properties exist and are not null.
Prevents unintentional overwriting of existing values with null.

Technical Summary:

if ($customer->network_address) {
    $this->setNetworkAddress($customer->network_address);
}

if ($customer->country_code) {
    $this->setCountryCode($customer->country_code);
}

Testing Notes:
Verified with and without network_address and country_code fields.
Confirmed that the setters trigger correctly only when valid values are passed.