perf: Test chunking with a lower amount of entries

Use a lower array_chunk values when running the code in the tests for
the comment manager.

Signed-off-by: Carl Schwan <carlschwan@kde.org>

lib/private/Comments/Manager.php

@@ -46,6 +46,9 @@ class Manager implements ICommentsManager {
 	/** @var \Closure[] */
 	protected array $displayNameResolvers = [];
 
+	// Modified by tests
+	protected int $chunkSize = 500;
+
 	public function __construct(
 		protected IDBConnection $dbConn,
 		protected LoggerInterface $logger,
@@ -1070,7 +1073,7 @@ class Manager implements ICommentsManager {
 			return [];
 		}
 
-		$chunks = array_chunk($commentIds, 500);
+		$chunks = array_chunk($commentIds, $this->chunkSize);
 
 		$query = $this->dbConn->getQueryBuilder();
 		$query->select('*')