Fixes items in storages sometimes lingering in observer UI (#90870)

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## About The Pull Request

doMove on item didn't account for observers, and while doUnEquip should
not be an issue, I've added the same observer image removal code as a
safeguard to it regardless.

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🆑
fix: Fixed items in storages sometimes lingering in observer UI
/🆑

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code/game/objects/items.dm

@@ -1319,19 +1319,23 @@
 	if (!ismob(loc))
 		return ..()
 
-	var/mob/M = loc
-	var/hand_index = M.get_held_index_of_item(src)
+	var/mob/owner = loc
+	var/hand_index = owner.get_held_index_of_item(src)
 	if(!hand_index)
 		return ..()
 
-	M.held_items[hand_index] = null
-	M.update_held_items()
-	if(M.client)
-		M.client.screen -= src
+	owner.held_items[hand_index] = null
+	owner.update_held_items()
+	if(owner.client)
+		owner.client.screen -= src
+	if(owner.observers?.len)
+		for(var/mob/dead/observe as anything in owner.observers)
+			if(observe.client)
+				observe.client.screen -= src
 	layer = initial(layer)
 	SET_PLANE_IMPLICIT(src, initial(plane))
 	appearance_flags &= ~NO_CLIENT_COLOR
-	dropped(M, FALSE)
+	dropped(owner, FALSE)
 	return ..()
 
 /obj/item/proc/canStrip(mob/stripper, mob/owner)

code/modules/mob/inventory.dm

@@ -380,18 +380,28 @@
 	if(hand_index)
 		held_items[hand_index] = null
 		update_held_items()
-	if(I)
-		if(client)
-			client.screen -= I
-		I.layer = initial(I.layer)
-		SET_PLANE_EXPLICIT(I, initial(I.plane), newloc)
-		I.appearance_flags &= ~NO_CLIENT_COLOR
-		if(!no_move && !(I.item_flags & DROPDEL)) //item may be moved/qdel'd immedietely, don't bother moving it
-			if (isnull(newloc))
-				I.moveToNullspace()
-			else
-				I.forceMove(newloc)
-		I.dropped(src, silent)
+
+	if(!I)
+		return FALSE
+
+	if(client)
+		client.screen -= I
+
+	if(observers?.len)
+		for(var/mob/dead/observe as anything in observers)
+			if(observe.client)
+				observe.client.screen -= I
+
+	I.layer = initial(I.layer)
+	SET_PLANE_EXPLICIT(I, initial(I.plane), newloc)
+	I.appearance_flags &= ~NO_CLIENT_COLOR
+	if(!no_move && !(I.item_flags & DROPDEL)) //item may be moved/qdel'd immedietely, don't bother moving it
+		if (isnull(newloc))
+			I.moveToNullspace()
+		else
+			I.forceMove(newloc)
+
+	I.dropped(src, silent)
 	SEND_SIGNAL(I, COMSIG_ITEM_POST_UNEQUIP, force, newloc, no_move, invdrop, silent)
 	SEND_SIGNAL(src, COMSIG_MOB_UNEQUIPPED_ITEM, I, force, newloc, no_move, invdrop, silent)
 	return TRUE