81beebe4b8
Grease Pencil animation data is stored in the object-data, not the `AnimData` of the Grease Pencil ID. This meant that the object was not properly tagged for an update, because the code assumed that the object had an `adt`. The fix calls `ANIM_id_update` to directly tag the Grease Pencil ID for an update (which will also update the Grease Pencil frames animation data).