Mismatch within base (zombie) villager texture

Relates to/clones part of MC-248555.

The base villager and base zombie villager texture have some mismatches within their textures.

Villager:

• The bottom of the feet are very dark, and do not match the skin color the rest of the feet have.

Zombie villager:

These are not as severe, but it is still quite a contrast; making them lighter should make it match while not really changing the texture much.

• The bottom of the feet are darker than the lowest pixels on the sides.

• The bottom of the hands (in texture layout, not in in-game model) are considerably darker than the lowest pixels on the sides.