SRF_Calender accesses private propery of Parser

Setup
* MediaWiki	1.40.4
* PHP	8.1.32 (apache2handler)
* MariaDB	10.6.22-MariaDB-0ubuntu0.22.04.1
* Semantic MediaWiki	5.0.2
* Semantic Result Formats	5.0.0

While updating my wiki I discovered that SRF access a private member of the Parser class in:
* \SRFCalendar::displayCalendar

This might be related to bug #553