Blender Git Loki

Fix T70787: Duplicating objects with custom property of type ID creates bogus links.

Note that the issue also affected animdata handling...

Checked all usages of the `BKE_libblock_copy_ex()` function, and
think never handling user count here is valid, although a bit risky
maybe. But other solution would be to add yet another copy flag, so
would rather go with that one for now.