fix the production sitemap request detection

ot_core/Classes/Middleware/Frontend/OtSitemapProvider.php

@@ -28,7 +28,7 @@ class OtSitemapProvider implements MiddlewareInterface
 
         $isSitemapRequest = $devMode ?
             preg_match("/[a-z0-9-]+\/sitemap\.xml/", $path) :
-            $path === 'sitemap.xml';
+            $path === '/sitemap.xml';
 
         if ($isSitemapRequest) {
             $path = $devMode ? substr($request->getUri()->getPath(), 0, -strlen('/sitemap.xml')) : '';