It was used to access evaluated object and pose and was done prior
to implementation of flushing values back to original data for an
active dependency graph.
Removing the argument allows to simplify API and solve issues with
accessing missing dependency graph on redo.
Animation: Remove depsgraph argument from a lot of API
Use explicit boolean flag to indicate whether flush to original data
is needed or not. Makes it possible to avoid confusion on whether an
evaluated or any depsgraph can be passed to the API.
Allows to remove depsgraph from bAnimContext as well.