[TASK] Add default arguments to getChildrenCategoriesRecursive()

Resolves: #61746
Change-Id: Ia65571277e9981238e45e14186ab25ef5d659a9d
Reviewed-on: http://review.typo3.org/33279
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>