fix: psalm issue

Signed-off-by: Julien Veyssier <julien-nc@posteo.net>

Author: julien-nc

lib/Migration/Version030500Date20260715083046.php

@@ -105,6 +105,6 @@ private function getDistinctUserIds(): array {
 		}
 
 		$userIds = array_unique(array_merge($userIdsChat, $userIdsAssignments));
-		return $userIds;
+		return array_values($userIds);
 	}
 }