Moving bones between skeletons may change the slot order.

[misaki-eymard]

Description:
When moving bones between skeletons, the order of the slots under the selected bone and the order of the slots under the child bones can be swapped.

Expected behavior:
Even if you move bones between skeletons, the order of the slots below the selected bone is maintained.

Steps to reproduce:

1. Download the attached .zip file: Moving bones between skeletons may change the slot order.zip
2. Open the Spine project that is inside the unzipped zip file in Spine 4.2.32.
3. Select bone1 in skeleton1 and drag and drop it onto the root bone in skeleton2.
   
4. You can see that the draw order of the child slots of bone2, slot1 and slot2, is now at the top, and the draw order of the child slots of bone1, slot3 and slot4, is now at the bottom.
   

The version of Spine in which this problem was found:
Spine 4.2.32

This problem was reported in the following thread on the forum:
https://jp.esotericsoftware.com/forum/d/26394-the-order-of-the-layers-changes-when-linking-bones-to-another-skeleton