Improve the support for new(er) versions of PHP in Moodle LMS.

The current timeline is:

• PHP 8.1 - Moodle 4.1.2 - DONE
• PHP 8.2 - Moodle 4.2.3 & 4.3 - DONE
• PHP 8.3 - Moodle 4.4 & Moodle 4.3.1 (and possibly Moodle 4.2.4)

The release date of Moodle 4.4 is 22nd April, 2024.

The current planned release date for PHP 8.3 is 23 November, 2023.