Parted 3.5 introduces the following regression:
- partition-set-flag sets the BIOS_GRUB flag. The partition type is set to
PARTITION_BIOS_GRUB_GUID.
- partition-set-system resets the partition type to PARTITION_LINUX_DATA_GUID
undoing what's done by partition-set-flag.
To prevent it, reverse the call order.
Fixes: <https://issues.guix.gnu.org/55549>.
* gnu/installer/parted.scm (mkpart): Call partition-set-system before
partition-set-flag.