Undoing animatable material type change does not refresh referenced materials

Steps to reproduce:
1. Create a new object and set its material to animatable
2. Import a custom material, and set it as the shader for the material in step 1
3. Create a 2nd object and set its material to reference the first object's material
4. Set the first object's shader to Standard
5. Undo

Result:
Only the first object is undone to the custom shader, referenced material does not refresh.

Notes:

• This was working fine before the new material system
• If this is fixed, it should also fix (QT3DS-2768) properly. We could remove the hot fix for that task after this one is fixed.