[Feature] Persist state of expanded/closed group layers on drag and drop

[K-Meech]

Is your feature request related to a problem? Please describe.

As noted in this PR, the expanded/closed state of groups doesn't persist on drag and drop. For example, make a group, add a few layers into it, then expand. Drag and drop the group to another position in the tree - the group will close, rather than remaining open.

Describe the solution you'd like
Group should remain expanded or closed when they are dragged and dropped to a new position in the tree.