Refactor dynamic segments listings to doctrine

[MAILPOET-3361]

lib/Segments/DynamicSegments/DynamicSegmentsListingRepository.php

@@ -0,0 +1,10 @@
+<?php
+
+namespace MailPoet\Segments\DynamicSegments;
+
+use MailPoet\Entities\SegmentEntity;
+use MailPoet\Segments\SegmentListingRepository;
+
+class DynamicSegmentsListingRepository extends SegmentListingRepository {
+  protected $types = [SegmentEntity::TYPE_DYNAMIC];
+}