Instead of assigning Actions by direct pointer manipulation (and the
corresponding juggling of user counts), call `animrig::assign_action()`
and `animrig::unassign_action()`.
These functions not only correctly handle user counts, but also ensure
that slot assignments & user tracking works. The former always happens,
the latter only when building with experimental features enabled.
Because (un)assigning slotted Actions need the animated ID (instead of
just the `AnimData *`), more functions now require an `OwnedAnimData`.
Note that there is still some user count juggling. This is caused by
`BKE_id_new()`, and by extension `BKE_action_add`, returning an ID with
user count = 1, even though that ID is not yet used. A todo task #128017
has been made to change `BKE_action_add()` so that the Action it returns
can be directly fed into `animrig::assign_action()`.
This PR updates the following areas:
- Creating a node group by grouping animated nodes, as this has to move
the animation data. This PR just handles the assignment of a new
Action.
- Temporary Action creation for ungrouping node groups.
- Versioning of pre-2.5 animation data.
No functional changes.
Ref: #123424
Pull Request: https://projects.blender.org/blender/blender/pulls/128026
6115132998