fix: Corrects country code check in statistics filter

Operator precedence made the check always true; it now accepts two capital letters or '--' as intended.

web/www/sunders/stats/index.php

@@ -84,8 +84,8 @@
         } else {
           $i18n = $i18nCountries;
           $i18nDefault = $i18nCountriesDefault;
-          // Check if $key consists of 2 capital letters.
-          $key = preg_match('/\b[A-Z]{2}\b/', $valsArray[$i]) === 1 || '--' ? $valsArray[$i] : 'dontfindme';
+          // Check if $key consists of 2 capital letters or is '--' (unknown country).
+          $key = (preg_match('/^[A-Z]{2}$/', $valsArray[$i]) === 1 || $valsArray[$i] === '--') ? $valsArray[$i] : 'dontfindme';
         }
         if (!isValidValue($i18n, $i18nDefault, $key)) {
           // ignore 'vals' and 'cols'