Some Mob Define Cleanup (#22536)

Just removing a few ancient 2008-era vars that were on every mob
globally, but were completely unused in the modern code. I thought about
removing the Mutations too, but since the Hulk mutation is actually used
by a tiny handful of things, I would probably have to do that in a
separate PR by turning the Hulk code into an Element instead.

code/modules/mob/mob_defines.dm

@@ -176,7 +176,6 @@
 	var/datum/hud/hud_used = null
 
 	var/list/grabbed_by = list(  )
-	var/list/requests = list(  )
 
 	var/list/mapobjs = list()
 
@@ -186,10 +185,6 @@
 
 	var/job = null//Living
 
-	var/const/blindness = 1//Carbon
-	var/const/deafness = 2//Carbon
-	var/const/muteness = 4//Carbon
-
 	var/can_pull_size = 10              // Maximum w_class the mob can pull.
 	var/can_pull_mobs = MOB_PULL_LARGER // Whether or not the mob can pull other mobs.
 
@@ -224,13 +219,6 @@
 //Wizard mode, but can be used in other modes thanks to the brand new "Give Spell" badmin button
 	var/list/spell/spell_list
 
-//List of active diseases
-
-	var/list/viruses = list() // replaces var/datum/disease/virus
-
-//Monkey/infected mode
-	var/list/resistances = list()
-
 	mouse_drag_pointer = MOUSE_ACTIVE_POINTER
 
 	var/update_icon = 1 //Set to 1 to trigger update_icon() at the next life() call