Resolve deprecation messages with PHP 8.1

[golenkovm]

This resolves #1

root@e7d21010cac7:/var/www/moodle# vendor/bin/phpunit --testsuite='local_kaltura_testsuite'
Moodle 4.2.3+ (Build: 20231020), 03bd101ede0a1ce62fdf8f63b9942933929ee6ea
Php: 8.1.2.1.2.14, pgsql: 14.0 (Debian 14.0-1.pgdg110+1), OS: Linux 6.2.0-35-generic x86_64
PHPUnit 9.5.28 by Sebastian Bergmann and contributors.

................................................................. 65 / 80 ( 81%)
...............                                                   80 / 80 (100%)

Time: 00:02.941, Memory: 82.50 MB

OK (80 tests, 182 assertions)

[golenkovm]

Closing this off in favour of kaltura/moodle_plugin#407 and kaltura/moodle_plugin#425