Blender Git Loki

UI: Expand linked/overriden collections by default in the Outliner

When linking or overriding an instanced collection, the new collection item in
the Outliner is now un-collapsed by default.
Linking and overriding is typically used in production scenes, where
collections tend to contain many items (children, grand-children, etc.). If all
collections in that hierarchy are expanded by default, the Outliner gets
flooded with items. So users ended up manually collapsing the collections.

Part of T76555.

Reviewed by: Andy Goralczyk, Bastien Montange.

Differential Revision: https://developer.blender.org/D7626