Add cancel snooze

- Add common request validation function

src/public/request/snooze.php

@@ -1,15 +1,11 @@
 <?php declare(strict_types=1);
 
-use MyPrayerJournal\{Auth, Request, Table, UI};
+use MyPrayerJournal\{Table, UI};
 use BitBadger\PDODocument\Patch;
 
 require '../../start.php';
-if ($_SERVER['REQUEST_METHOD'] <> 'PATCH') not_found();
 
-Auth::requireUser(false);
-
-$req = Request::byId($_GET['id']);
-if (!$req) not_found();
+$req = validate_request($_GET['id'], ['PATCH'], false);
 
 $until = (new DateTimeImmutable($_PATCH['until'] . 'T00:00:00', new DateTimeZone($_REQUEST['time_zone'])))
              ->setTimezone(new DateTimeZone('Etc/UTC'));