[AssetMapper] Upgrade importmap polyfill

Not sure if we should backport this on 6.4 ?

Author: smnandre

src/Symfony/Component/AssetMapper/ImportMap/ImportMapRenderer.php

@@ -27,7 +27,9 @@
  */
 class ImportMapRenderer
 {
-    private const DEFAULT_ES_MODULE_SHIMS_POLYFILL_URL = 'https://ga.jspm.io/npm:[email protected]/dist/es-module-shims.js';
+    // https://generator.jspm.io/#S2NnYGAIzSvJLMlJTWEAAMYOgCAOAA
+    private const DEFAULT_ES_MODULE_SHIMS_POLYFILL_URL = 'https://ga.jspm.io/npm:[email protected]/dist/es-module-shims.js';
+    private const DEFAULT_ES_MODULE_SHIMS_POLYFILL_INTEGRITY = 'sha384-ie1x72Xck445i0j4SlNJ5W5iGeL3Dpa0zD48MZopgWsjNB/lt60SuG1iduZGNnJn';
 
     public function __construct(
         private readonly ImportMapGenerator $importMapGenerator,