Minimal changes to make Rigify use the current Action API (introduced in
Blender 4.4) instead of the legacy API (removed in 5.0).
Most of the refactoring consists of:
- Find the right `Channelbag`
- Replace operations on `Action` with operations on that `Channelbag`.
I didn't manage to test all code, because some code paths are very hard
to follow, and others seem to only be available for legacy rigs.
This is part of #146586
Pull Request: https://projects.blender.org/blender/blender/pulls/147060
7b18a2c324