Ensure loadAddons returns an array

[otacke]

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What kind of change does this PR introduce?
Bug fix

What is the current behaviour?
The H5P framework interface requires the loadAddon function to return an array (https://github.com/h5p/h5p-php-library/blob/cb64a1f3884408487c3178e31fc140f5d45ca165/h5p.classes.php#L110-L114). However, the current implementation will return null if the SQL query fails (

h5p-wordpress-plugin/public/class-h5p-wordpress.php

Lines 861 to 873 in 2a60665

	public function clearFilteredParameters($library_ids) {
	global $wpdb;
	$wpdb->query(
	"UPDATE {$wpdb->prefix}h5p_contents
	SET filtered = ''
	WHERE id IN (
	SELECT DISTINCT content_id
	FROM {$wpdb->prefix}h5p_contents_libraries
	WHERE library_id IN (" . implode(',', array_map('intval', $library_ids)) . ")
	)"
	);
	}

).

What is the new behaviour?
If the SQL query fails, an empty array will be returned (silently failing) to honor the interface.

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• I searched for existing issues/PRs first
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• I tested my changes locally

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[arzola]

This makes sense

[otacke]

@arzola So this could be moved to "Verified by Community Maintainer"? Do you have the rights to do that already?