Undead Bush

Makes the Bush plant added in the 25w05a snapshot look more like a variant of the already existing Dead Bush, rather than being a whole new thing.

The texture is split into 2 layers, so that when the plant is placed on the ground, only the leaves have the biome tint applied (see photos in the gallery tab). Also, the item texture now has the color of the leaves baked in, instead of using a tint index.