In addition:
* SmartObjectCollection got deprecated and there's a auto-update path triggered in SmartObjectCollection::PostLoad
* SmartObjectComponent component can opt out of being a part of a collection with `bCanBePartOfCollection`
* Right now we limit SmartObjects to be registered with at most a single Collection. This might change in the future if required.
Note that this is the first change in a series, we're going to support miltiple collections per level with convenient ways of assigning SmartObjects to individual collections.
#jira UE-168977
#preflight 637f8faa4004f73f627ecaca
#preflight 637fa5378b12eb83a77ad7d9
[CL 23262132 by mieszko zielinski in ue5-main branch]