Blender Git Loki

Fix T76997: bad handling of embedded IDs in partial append.

Code dealing with embedded data was pre-existing proper generic
handling of those by `BKE_library_foreach_ID_link()` - and was never
updated for scene's master collection it would seem...

Note that such fix/refactor is a bit risky at this point in the release
cycle, but on the other end previous situation was really broken. So
finger crossed. :|