Slime and honey blocks don't render correctly in inventories

This issue can be possibly fixed by adding a separate inventory model using the old model, so when placed it does the cull-facing properly and also displays properly in the inventory.

So in other words, the old model = used for inventory
the new model = block itself

That would fix the issue, but it would be nice if we could get a more permanent fix for this graphical issue so extra files would be unnecessary.

Confirmed for 1.13.1.

As of the 1.15 rendering engine update, slime blocks render correctly in all cases now except for when in inventories.

Confirmed in 1.16 Release Candidate 1.

Forward resolved this as a duplicate of MC-157727 as that report already has a priority set.