Update resources/views/themes/default/index.blade.php

null coalesce for possible missing config value

Co-authored-by: Shalvah <shalvah@users.noreply.github.com>

resources/views/themes/default/index.blade.php

@@ -26,7 +26,7 @@
         var baseUrl = "{{ $tryItOut['base_url'] ?? config('app.url') }}";
         var useCors = Boolean({{ $tryItOut['use_cors'] ?? null }});
         var useCsrf = Boolean({{ $tryItOut['use_csrf'] ?? null }});
-        var csrfUrl = "{{ $tryItOut['csrf_url'] }}";
+        var csrfUrl = "{{ $tryItOut['csrf_url'] ?? null }}";
         var csrfCookieName = "{{ $tryItOut['csrf_cookie_name'] ?? "XSRF-TOKEN" }}";
     </script>
     <script src="{{ u::getVersionedAsset($assetPathPrefix.'js/tryitout.js') }}"></script>