Merge pull request #31314 from nextcloud/backport/31309/stable22

[stable22] Avoid PHP errors in the checkers drone step

build/triple-dot-checker.php

@@ -32,7 +32,7 @@
 	$it = new \RecursiveDirectoryIterator($dir);
 
 	foreach (new RecursiveIteratorIterator($it) as $file) {
-		if ($file->getExtension() === 'map') {
+		if (($file->getExtension() === 'map') || $file->isDir()) {
 			continue;
 		}
 		$content = file_get_contents($file->getPathname());