[Bug 2.9.1] Undoing manual levels on NIP's does not undo if no background state is present; turns into temporary home levels

I haven't tested this on a full console, just on my computer at home without a rig attached, but the output was verified in sACN viewer and a visualizer.

1) Patch any fixture which has non-intensity parameters.
2) Change NIP levels manually
3) Undo the manual commands.
4) The displayed home values of the fixture (light grey) are now set to the previous manual levels--effectively, the levels were not undone.
5) Sneak or Home restores the proper home values.

The bug won't occur if the parameter has a background state to go to.