Converted mobs don't keep their rotation (facing)

Converted mobs always have their rotation set to 0,0 (south) after converting.

Reproduction Steps

• Do /tick freeze
• Spawn a piglin
• Do /tick step 300t
• Once that's done do /tick step 1t

Observed Results

• The mob loses whatever rotation it had and starts facing south
  rotation.mp4

Expected Results

• The mob would keep its rotation data