Apply suggestions from code review

Author: BurntimeX

files/lib/data/conversation/ConversationCollection.class.php

@@ -121,10 +121,6 @@ private function loadAssignedLabels(): void
         $statement = WCF::getDB()->prepare($sql);
         $statement->execute($conditions->getParameters());
         while ($row = $statement->fetchArray()) {
-            if (!isset($this->assignedLabels[$row['conversationID']])) {
-                $this->assignedLabels[$row['conversationID']] = [];
-            }
-
             $this->assignedLabels[$row['conversationID']][$row['labelID']] = $labels[$row['labelID']];
         }
     }
@@ -192,7 +188,7 @@ private function loadParticipantSummaries(): void
             \array_merge($conditions->getParameters(), [5])
         );
 
-        $rows = $statement->fetchAll();
+        $rows = $statement->fetchAll(\PDO::FETCH_ASSOC);
         foreach ($rows as $row) {
             if ($row['userID']) {
                 UserProfileRuntimeCache::getInstance()->cacheObjectID($row['userID']);

files/lib/data/conversation/message/ConversationMessageCollection.class.php

@@ -167,7 +167,7 @@ private function loadTeaserImages(): void
             \array_merge($conditions->getParameters(), [1])
         );
 
-        $rows = $statement->fetchAll();
+        $rows = $statement->fetchAll(\PDO::FETCH_ASSOC);
         foreach ($rows as $row) {
             FileRuntimeCache::getInstance()->cacheObjectID($row['fileID']);
         }

files/lib/data/conversation/participant/ConversationParticipantAction.class.php

@@ -14,4 +14,4 @@
  *
  * @extends AbstractDatabaseObjectAction<ConversationParticipant, ConversationParticipantEditor>
  */
-class UserRankAction extends AbstractDatabaseObjectAction {}
+class ConversationParticipantAction extends AbstractDatabaseObjectAction {}