Update error-handling, not all warnings should be shown to all users

phpcs-errors:253 phpunit-status:successful

csv_check.php

@@ -1,7 +1,7 @@
 <?PHP
 declare(strict_types = 1);
 error_reporting(E_ALL);
-ini_set('display_errors', "1");
+ini_set('display_errors', "0");
 
 require_once __DIR__ . "/functions/functions.php";
 

index3.php

@@ -1,5 +1,6 @@
 <?PHP
 declare(strict_types = 1);
+
 require_once __DIR__ . "/functions/functions.php";
 
 echo printHTMLHead();