FIX: handle undefined cookie value for virtual card expansion, refact…

[Maxenor]

Fix "Undefined array key" warning and remove debug output in virtualcard.php

Summary

Replaced direct access to $_COOKIE['virtualcard_expand'] with the null coalescing operator to avoid the "Undefined array key" warning.

Why

Undefined array key warning: Accessing $_COOKIE['virtualcard_expand'] directly triggered a warning if the cookie didn’t exist.

@defrance

[eldy]

Use of ob_start lead to difficulty to understand and debug.
We should not need this for common pages.
Can you describe why you need this ?

According to description of bug, only the
$expand = $_COOKIE['virtualcard_expand'] ?? null;
should be required

[Maxenor]

Hello, there were multiple errors displaying on the virtual card page with headers already sent by the main.inc.php file. It helps prevent "headers already sent" errors by delaying the actual sending of output until the page's ready, allowing to modify headers at any point before the flush.

[eldy]

Hello, there were multiple errors displaying on the virtual card page with headers already sent by the main.inc.php file. It helps prevent "headers already sent" errors by delaying the actual sending of output until the page's ready, allowing to modify headers at any point before the flush.

If we have error "headers already sent", it is better to fix them by not sending data before the header instead of adding a hack to hide it.

[hregis]

@Maxenor and if multiple errors... fix this errors ! ;-)