refactor(http): remove redundant enum guard

Signed-off-by: memleakd <121398829+memleakd@users.noreply.github.com>

Author: memleakd

system/HTTP/ValidatedInput.php

@@ -13,7 +13,6 @@
 
 namespace CodeIgniter\HTTP;
 
-use BackedEnum;
 use CodeIgniter\Exceptions\InvalidArgumentException;
 use CodeIgniter\I18n\Time;
 use DateTimeZone;
@@ -211,10 +210,6 @@ private function backedEnum(string $key, string $enumClass, ReflectionEnum $refl
             throw $this->invalidType($key, $enumClass);
         }
 
-        if (! is_subclass_of($enumClass, BackedEnum::class)) {
-            throw $this->invalidType($key, $enumClass);
-        }
-
         if ($backingType === 'string') {
             $value = (string) $value;
         }