ge: add trade seq number

Occasionally the trades are delivered out of order, this allows us to reassemble them in the correct order

http-api/src/main/java/net/runelite/http/api/ge/GrandExchangeTrade.java

@@ -42,4 +42,5 @@ public class GrandExchangeTrade
 	private int offer;
 	private int slot;
 	private WorldType worldType;
+	private int seq;
 }