Fix HEV armor not fully initializing (#3491)

## About The Pull Request

`ADD_TRAIT`/`REMOVE_TRAIT` don't take lists you need to use a proc for
that

## Why It's Good For The Game

Fixes #3484

## Proof Of Testing
<details>
<summary>Screenshots/Videos</summary>


![image](https://github.com/user-attachments/assets/c11c26f8-2f80-44c8-8f94-513155b7f316)

</details>

## Changelog
🆑
fix: fixed HEV suit not turning on properly
/🆑

modular_skyrat/modules/hev_suit/code/hev_suit.dm

@@ -641,7 +641,7 @@
 	send_hev_sound(radiation_sound)
 
 /obj/item/clothing/suit/space/hev_suit/proc/weaponselect()
-	ADD_TRAIT(current_user, list(TRAIT_GUNFLIP,TRAIT_GUN_NATURAL), "hev_trait")
+	current_user.add_traits(list(TRAIT_GUNFLIP,TRAIT_GUN_NATURAL), "hev_trait")
 	playsound(src, weaponselect_sound, 50)
 	send_message("...CALIBRATED", HEV_COLOR_GREEN)
 	send_message("CALIBRATING MUNITION LEVEL MONITORING SYSTEMS...")
@@ -681,7 +681,7 @@
 		REMOVE_TRAIT(current_internals_tank, TRAIT_NODROP, "hev_trait")
 	if(current_user)
 		send_message("SYSTEMS DEACTIVATED", HEV_COLOR_RED)
-		REMOVE_TRAIT(current_user, list(TRAIT_GUNFLIP,TRAIT_GUN_NATURAL), "hev_trait")
+		current_user.remove_traits(list(TRAIT_GUNFLIP,TRAIT_GUN_NATURAL), "hev_trait")
 		UnregisterSignal(current_user, list(
 			COMSIG_ATOM_ACID_ACT,
 			COMSIG_CARBON_GAIN_WOUND,