More istypes replaced with helpers (#20767)

* shouldn't you be merging these by now

* my oh my do we have a lot of these

* a fellow pedantic shit

code/modules/admin/admin_verbs.dm

@@ -358,7 +358,7 @@ var/list/admin_verbs_hideable = list(
 	set name = "Aghost"
 	if(!holder)
 		return
-	if(istype(mob,/mob/dead/observer))
+	if(isobserver(mob))
 		//re-enter
 		var/mob/dead/observer/ghost = mob
 		if(!ghost.mind || !ghost.mind.current) //won't do anything if there is no body
@@ -369,7 +369,7 @@ var/list/admin_verbs_hideable = list(
 		ghost.can_reenter_corpse = 1 //force re-entering even when otherwise not possible
 		ghost.reenter_corpse()
 		feedback_add_details("admin_verb","P") //If you are copy-pasting this, ensure the 2nd parameter is unique to the new proc!
-	else if(istype(mob,/mob/new_player))
+	else if(isnewplayer(mob))
 		src << "<font color='red'>Error: Aghost: Can't admin-ghost whilst in the lobby. Join or Observe first.</font>"
 	else
 		//ghostize