The wither's skull projectile attacks do not account for the scale attribute

The wither's skull projectile attacks do not account for the wither's scale attribute, leading the attacks to come from an unexpected position either above or below the wither, disconnected from it.

Steps to Reproduce:

^{(Requires survival)}

1. Give the player regeneration (For ease of reproducing the issue)

   /effect give @p minecraft:regeneration infinite 255 true

2. Summon a wither

   /summon minecraft:wither ~ ~ ~

3. Modify the wither's scale

   /attribute @e[type=wither,limit=1] minecraft:generic.scale base set 5

Screenshots/Videos:

Notes:

1. Similar to MC-267418, this is not about the size of the projectile/attack, but instead is purely about it's position relative to the entity shooting it. With other entities such as a skeleton, the behavior is correct.

2. Relations:
   MC-267418 MC-267372 MC-267427 MC-267706 MC-267707 MC-267416