[No GBP] Fixes slow slime feed (#82284)

## About The Pull Request

Slimes were supposed to gain the same amount of nutrition as the damage
they dealt while feeding. However, I have accidentally multiplied this
again by `seconds_between_ticks` a second time. This meant that locally
slimes fed normally, but on the server they got about the third
nutrition they were supposed to, probably due to having more ticks per
second then my machine. This PR fixes that.

Also raised the nutrition gained by slimes by 20%, after careful
testing, one monkey wasn't always enough.

## Why It's Good For The Game

 Fixes #82283

## Changelog

🆑
fix: Slimes now feed faster, and should only need one monkey to reach
their next lifestage.
/🆑

code/datums/status_effects/debuffs/slime/slime_leech.dm

@@ -87,7 +87,7 @@
 
 		to_chat(owner, span_userdanger(pick(pain_lines)))
 
-	our_slime.adjust_nutrition(-1 * 1.6 * totaldamage * seconds_between_ticks)
+	our_slime.adjust_nutrition(-1 * 1.8 * totaldamage) //damage is already modified by seconds_between_ticks
 
 	//Heal yourself.
 	our_slime.adjustBruteLoss(-1.5 * seconds_between_ticks)