bootctl: handle if LoaderSystemToken is invalid for some reason
This points to some firmware issue, but we should still be able to
correct things if this happens. Hence log about this and fix it.
Fixes: #17041
(cherry picked from commit ad0b610b)
(cherry picked from commit a06cf9a5)
(cherry picked from commit 387881ae)
(cherry picked from commit 9f6249eb)