SUSE-SU-2025:4224-1

This update for grub2 fixes the following issues:

• CVE-2025-54771: Fixed rub_file_close() does not properly controls the fs refcount (bsc#1252931)
• CVE-2025-61661: Fixed out-of-bounds write in grub_usb_get_string() function (bsc#1252932)
• CVE-2025-61662: Fixed missing unregister call for gettext command may lead to use-after-free (bsc#1252933)
• CVE-2025-61663: Fixed missing unregister call for normal commands may lead to use-after-free (bsc#1252934)
• CVE-2025-61664: Fixed missing unregister call for normal_exit command may lead to use-after-free (bsc#1252935)

Other fixes:

• Bump upstream SBAT generation to 6