fix(activity): Also don't log previous description

Signed-off-by: Joas Schilling <coding@schilljs.com>

Author: nickvergessen

lib/Activity/ActivityManager.php

@@ -406,7 +406,7 @@ private function createEvent($objectType, $entity, $subject, $additionalParams =
 
 			if ($subject === self::SUBJECT_CARD_UPDATE_DESCRIPTION && isset($params['after'])) {
 				$newContent = $params['after'];
-				unset($params['before'], $params['after'], $params['card']['description']);
+				unset($params['before'], $params['after'], $params['card']['description'], $params['card']['descriptionPrev']);
 
 				$params['after'] = mb_substr($newContent, 0, self::SHORTENED_DESCRIPTION_MAX_LENGTH);
 				if (mb_strlen($newContent) > self::SHORTENED_DESCRIPTION_MAX_LENGTH) {