[MIRROR] Adds IS_TRAITOR macro [MDB IGNORE] (#20153)

* Adds IS_TRAITOR macro (#74293)

## About The Pull Request
i was making another PR and found that we have cultist, heretic, and
nuke op IS macros but not one for traitors
this adds one and then replaces it where applicable, mostly in checks
where a traitor device does something different if you are not a traitor

## Why It's Good For The Game

better for people making traitor only devices to have this macro, as it
is more clear and also cleaner in general i think

## Changelog

🆑
code: adds IS_TRAITOR macro
/🆑

* Adds IS_TRAITOR macro

---------

Co-authored-by: Sol N <116288367+flowercuco@users.noreply.github.com>

code/modules/antagonists/traitor/objectives/locate_weakpoint.dm

@@ -245,7 +245,7 @@
 	if(!user.mind)
 		return
 
-	if(!user.mind.has_antag_datum(/datum/antagonist/traitor))
+	if(!IS_TRAITOR(user))
 		to_chat(user, span_warning("You can't seem to find a way to detonate the charge."))
 		return
 

code/modules/antagonists/traitor/objectives/sabotage_machinery.dm

@@ -153,7 +153,7 @@ GLOBAL_DATUM_INIT(objective_machine_handler, /datum/objective_target_machine_han
 
 /obj/item/traitor_machine_trapper/examine(mob/user)
 	. = ..()
-	if(!user.mind?.has_antag_datum(/datum/antagonist/traitor))
+	if(!IS_TRAITOR(user))
 		return
 	if(target_machine_path)
 		. += span_notice("This device must be placed by <b>clicking on a [initial(target_machine_path.name)]</b> with it. It can be removed with a screwdriver.")

code/modules/antagonists/traitor/objectives/steal.dm

@@ -265,7 +265,7 @@ GLOBAL_DATUM_INIT(steal_item_handler, /datum/objective_item_handler, new())
 	if(planted_on)
 		return
 
-	if(user.mind?.has_antag_datum(/datum/antagonist/traitor))
+	if(IS_TRAITOR(user))
 		if(target_object_type)
 			. += span_notice("This device must be placed by <b>clicking on the [initial(target_object_type.name)]</b> with it.")
 		. += span_notice("Remember, you may leave behind fingerprints or fibers on the device. Use <b>soap</b> or similar to scrub it clean to be safe!")