grub installation: fix: simplify code

my @prevDeviceTargets = split/:/, $prevGrubState->devices;

my $devicesDiffer = scalar (List::Compare->new( '-u', '-a', \@deviceTargets, \@prevDeviceTargets)->get_symmetric_difference());

my $nameDiffer = !(get("fullName") eq $prevGrubState->name);

my $versionDiffer = !(get("fullVersion") eq $prevGrubState->version);

my $efiDiffer = !($efiTarget eq $prevGrubState->efi);

my $efiMountPointDiffer = !($efiSysMountPoint eq $prevGrubState->efiMountPoint);

my $nameDiffer = get("fullName") ne $prevGrubState->name;

my $versionDiffer = get("fullVersion") ne $prevGrubState->version;

my $efiDiffer = $efiTarget ne $prevGrubState->efi;

my $efiMountPointDiffer = $efiSysMountPoint ne $prevGrubState->efiMountPoint;

my $requireNewInstall = $devicesDiffer || $nameDiffer || $versionDiffer || $efiDiffer || $efiMountPointDiffer || (($ENV{'NIXOS_INSTALL_GRUB'} // "") eq "1");

# install a symlink so that grub can detect the boot drive when set