reverts #18618, fixing the melee attack chain (#18687)

* reverts #18618

* refixes the chainsaw

code/game/objects/items/weapons/twohanded.dm

@@ -627,7 +627,7 @@
 		else
 			if(target.stat != DEAD)
 				user.apply_status_effect(STATUS_EFFECT_CHAINSAW_SLAYING)
-			if(..())
+			if(isnull(..())) // attack returns null if the attack was successful, (against humans)
 				target.KnockDown(8 SECONDS)
 		return
 	else

code/modules/mob/living/carbon/human/human_defense.dm

@@ -473,7 +473,6 @@ emp_act
 		bonus_damage = H.physiology.melee_bonus
 
 	apply_damage(I.force + bonus_damage , I.damtype, affecting, armor, sharp = weapon_sharp, used_weapon = I)
-	. = TRUE // at this point the attack has succeeded.
 
 	var/bloody = 0
 	if(I.damtype == BRUTE && I.force && prob(25 + I.force * 2))