Blender Git Loki

Fix T69931: Materials with keyframes duplicated by 'make single user' are linked.

Another sneaky bite from the infamous private ID data: While those
monsters are not in bmain, the actions used by their animdata are
regular cute little ID's, living with the herd in the safe and sound
Main DB...

So we have to be careful not to propagate the nasty black magic
required to handle the formers when we duplicate their animdata.

Saying it again: private ID datablocks should never have had their own
animdata & actions, this is endless issue also with RNA paths... And
makes copying of animation between materials and such needlessly
complicated.