c6b553d57c added the bone collection in
outliner. However, there is change in tree element order when switched
between pose and edit/object mode. Because order of tree building is
`edit bones -> bone collection -> pose bones`
To keep tree structure consistent between different modes, first draw
pose bone and then the ebone/bone collection.
Pull Request: https://projects.blender.org/blender/blender/pulls/112908