Merge pull request #33276 from nextcloud/backport/33270/stable24

[stable24] fix loading legacy app.php with multi app dir

Author: blizzz

lib/private/legacy/OC_App.php

@@ -183,7 +183,7 @@ public static function loadApp(string $app) {
 				'app' => $app,
 			]);
 			try {
-				self::requireAppFile($app);
+				self::requireAppFile($appPath);
 			} catch (Throwable $ex) {
 				if ($ex instanceof ServerNotAvailableException) {
 					throw $ex;