Making MailerPress Email Campaign Previews Indexable

// Make all email campaigns indexable
add_filter('mailerpress_campaign_preview_noindex', '__return_false');

// To set a specific email campaign indexable
add_filter('mailerpress_campaign_preview_noindex', 'mailerpress_campaign_preview_noindex', 10, 2);
function mailerpress_campaign_preview_noindex($noindex, $campaign_id) {
    if ($campaign_id === 123) {
        return false; // Indexable
    }
    return $noindex; // Keep default behavior (noindex)
};