Code review comment for ~raharper/curtin:fix/uefi-remove-dups-v2

In https://bugs.launchpad.net/maas/+bug/1894217/comments/3, it looks like there are two issues: (a) we're incorrectly detecting duplicates, and (b) we might remove the BootCurrent value. This branch definitely addresses (b); does it also intend to address (a)?