Blushing matches blood color (#95074)

## About The Pull Request

Blushing's color is generated from blood color, so lizards have green
blushing and whatnot.

<img width="102" height="90" alt="image"
src="https://github.com/user-attachments/assets/b206b29c-f8a8-4dc4-b091-8d7e8f080fc3"
/>

## Why It's Good For The Game

Blushing is when you get more blood in yo face so it wouldn't make sense
to be red(pink) for people without red blood.

## Changelog

🆑 Melbert
qol: Blushing matches blood color, so lizards blush greeeen.
/🆑

code/modules/surgery/bodyparts/_bodyparts.dm

@@ -116,8 +116,6 @@
 
 	///the type of damage overlay (if any) to use when this bodypart is bruised/burned.
 	var/dmg_overlay_type = "human"
-	///a color (optionally matrix) for the damage overlays to give the limb
-	var/damage_overlay_color
 	/// If we're bleeding, which icon are we displaying on this part
 	var/bleed_overlay_icon