3fbff8c83f
When reactivating a newsletter with many queues (e.g., a welcome email with a long history)
NewsletterEntity::getQueues may fail because it attempts to fetch all queues and instantiate
many entity objects.
In this commit, I optimize this by looking only into unfinished queues.
getUnfinishedQueues look for where countToProcess is higher than 0.
We set the count for welcome emails when we create a new queue
see f1ffc77bf3/mailpoet/lib/Newsletter/Scheduler/WelcomeScheduler.php (L140)
[MAILPOET-6310]