Animation indicators as well as decorators for properties were not
updating correctly in the following cases:
- NLA pushdown (this was reported in T87681)
- NLA enter/exit tweakmode
- Outliner unlinking/setting action
These actions all send a ND_NLA_ACTCHANGE notifier which the Properties
Editor was not listening to [which is now added].
part of T87681.
Maniphest Tasks: T87681
Differential Revision: https://developer.blender.org/D11040