BUGFIX - payment methods provider filters fixed

[ebaranauskas]

• Payment methods provider fix.

null amount when searching for payment methods was treated as 0 so it did not return any payment methods. I think, it should return all enabled project payment methods instead. Null currency did not work, no point to allow searching by it.

Fixed both issues, yet I suggest adapting my PR according your standards. It's quite strange that resulting file WebToPay.php got so different for me...

Issue demonstration:

erikas@zen:~/Projects/test$ cat test.php 
<?php

require_once 'WebToPay.php';


explainResult(WebToPay::getPaymentMethodList(6028, null, 'EUR'));
explainResult(WebToPay::getPaymentMethodList(6028, 0, 'EUR'));
explainResult(WebToPay::getPaymentMethodList(6028, 100, 'EUR'));
explainResult(WebToPay::getPaymentMethodList(6028, 100, null));

function explainResult(WebToPay_PaymentMethodList $list): void
{
    printf("LT payment methods found: %d\n", count((array) $list->getCountry('lt')?->getPaymentMethods()));
}
erikas@zen:~/Projects/test$ php test.php #before my changes
LT payment methods found: 0
LT payment methods found: 0
LT payment methods found: 13
PHP Fatal error:  Uncaught TypeError: WebToPay_PaymentMethodList::__construct(): Argument #2 ($currency) must be of type string, null given, called in /home/erikas/Projects/test/WebToPay.php on line 1557 and defined in /home/erikas/Projects/test/WebToPay.php:1258
Stack trace:
#0 /home/erikas/Projects/test/WebToPay.php(1557): WebToPay_PaymentMethodList->__construct()
#1 /home/erikas/Projects/test/WebToPay.php(253): WebToPay_PaymentMethodListProvider->getPaymentMethodList()
#2 /home/erikas/Projects/test/test.php(9): WebToPay::getPaymentMethodList()
#3 {main}
  thrown in /home/erikas/Projects/test/WebToPay.php on line 1258

erikas@zen:~/Projects/test$ php test.php #after my changes
LT payment methods found: 16
LT payment methods found: 0
LT payment methods found: 13
PHP Fatal error:  Uncaught TypeError: WebToPay_PaymentMethodListProvider::getPaymentMethodList(): Argument #2 ($currency) must be of type string, null given, called in /home/erikas/Projects/test/WebToPay.php on line 253 and defined in /home/erikas/Projects/test/WebToPay.php:1082
Stack trace:
#0 /home/erikas/Projects/test/WebToPay.php(253): WebToPay_PaymentMethodListProvider->getPaymentMethodList()
#1 /home/erikas/Projects/test/test.php(9): WebToPay::getPaymentMethodList()
#2 {main}
  thrown in /home/erikas/Projects/test/WebToPay.php on line 1082
erikas@zen:~/Projects/test$

[ebaranauskas]

Found some problems with it. Will present new changes latter. Closing this one till then.