Fix programming error causing undefined property access when dynamic value is unset

Dynamic property access ($row->{$column}) caused PHP warnings when `$value` was
undefined, resulting in attempts to read non-existent properties. Updated the
logic to use null coalescin, which safely returns `null` for missing properties
and prevents these warnings.

Author: sukhwinder33445

src/Filter.php

@@ -536,11 +536,7 @@ protected function performMatch(Rule $rule, $row)
      */
     protected function extractValue($column, $row)
     {
-        try {
-            return $row->{$column};
-        } catch (Throwable $_) {
-            return null;
-        }
+        return $row->$column ?? null;
     }
 
     /**