Re-submitting Upload requests isn't supported yet

When a request is saved for later replay (SavedRequestManager) — e.g. on CSRF token expiry (resubmit confirmation) or login detour — only the request parameters, method and headers are stored. Multipart file content is not saved, so replaying an upload request silently loses the attached file(s).

Additionally, the restored request (SavedRequestWrapper) has no multipart body, so FileUploadUtils.getFileItems() finds no file items, meaning the Upload action cannot work on a restored request at all.

Either the saved request should also persist the uploaded parts, or the user should at least be informed that the file must be re-selected instead of failing silently.