Fix check for not splitting an LV between two VGs in case
where the LVs contains an internal layer.

For example, integrity layer for RAIDs and splitting a PV that
is not part of the RAID LV at all (sdc here):

❯ vgcreate vg /dev/sda /dev/sdb /dev/sdc
Volume group "vg" successfully created

❯ lvcreate -l1 -m1 --type raid1 --raidintegrity y vg /dev/sda /dev/sdb
Logical volume "lvol0" created.

Before this patch:

❯ vgsplit vg vg2 /dev/sdc
Logical volume vg/lvol0_rimage_0 (part of lvol0) must be inactive.

❯ vgchange -an vg
0 logical volume(s) in volume group "vg" now active

❯ vgsplit vg vg2 /dev/sdc
Can't split LV lvol0_rimage_0 between two Volume Groups

With this patch applied:

❯ vgsplit vg vg2 /dev/sdc
New volume group "vg2" successfully split from "vg"