Adjust filter plugin validation requirements to comply with Moodle 4.5 #713

Job	Run time
CI test (make validate)	1m 4s
Code coverage (codecov)	54s
Integration tests (8.3, main, true)	6m 41s
Build moodle-plugin-ci.phar	31s
Integration tests (8.3, MOODLE_405_STABLE, true)	6m 43s
Integration tests (8.3, MOODLE_404_STABLE, true)	6m 20s
Integration tests (8.2, MOODLE_403_STABLE, true)	6m 28s
Integration tests (8.2, MOODLE_402_STABLE, true)	6m 7s
Integration tests (8.1, MOODLE_401_STABLE, true)	6m 38s
Integration tests (8.0, MOODLE_400_STABLE)	5m 38s
Integration tests (8.0, MOODLE_311_STABLE)	5m 12s
Integration tests (7.4, MOODLE_39_STABLE)	4m 53s
SelfUpdate tests (PHAR) (8.3)	37s
Integration tests (PHAR) (8.3, main, true)	6m 5s
SelfUpdate tests (PHAR) (8.2)	33s
Integration tests (PHAR) (8.3, MOODLE_405_STABLE, true)	6m 14s
SelfUpdate tests (PHAR) (8.1)	19s
Integration tests (PHAR) (8.3, MOODLE_404_STABLE, true)	5m 42s
SelfUpdate tests (PHAR) (8.0)	22s
Integration tests (PHAR) (8.2, MOODLE_403_STABLE, true)	6m 6s
SelfUpdate tests (PHAR) (7.4)	13s
Integration tests (PHAR) (8.1, MOODLE_402_STABLE, true)	5m 30s
Integration tests (PHAR) (8.0, MOODLE_401_STABLE, true)	6m 24s
Integration tests (PHAR) (7.4, MOODLE_400_STABLE)	4m 59s
	1h 40m 13s

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