This adds a `VArray::from_std_func` next to the existing `VArray::from_func`. It
does almost the same but inserts some type erasure by using `std::function`
which avoids the need to instantiate the full virtual array. This has is a bit
slower at run-time, but in practice there are some cases where it doesn't
matter. Currently, this patch reduces binary size by ~35kb. Not too much, but
still good or such a simple change.
Pull Request: https://projects.blender.org/blender/blender/pulls/146011
10353b3d69