Updated bot casting roles to not refresh with every spell cast (oversight in recent casting chances commit)

zone/bot_structs.h

@@ -60,6 +60,11 @@ struct BotSpell_wPriority : public BotSpell {
 	uint8 Priority;
 };
 
+struct BotCastingRoles {
+	bool GroupHealer;
+	bool GroupSlower;
+};
+
 struct BotAA {
 	uint32 aa_id;
 	uint8 req_level;