restore clearcache second arg as non required

ot_core/Classes/Cache/OtCacheManager.php

@@ -29,7 +29,7 @@ class OtCacheManager
      * @param int $pageUid
      * @param bool $clearAll if true, all caches will be cleared, and not only the frontend one
      */
-    public static function clearSiteCache(int $pageUid, bool $clearAll) {
+    public static function clearSiteCache(int $pageUid, bool $clearAll = false) {
 
         $pageRepository = GeneralUtility::makeInstance(ObjectManager::class)->get(OtPageRepository::class);
         $rootPage = $pageRepository->getRootPageFor($pageUid);