Core/SAI: Implement waiting for actions on action list to finish before continuing the action list

This is enabled by setting event_flags to SMART_EVENT_FLAG_ACTIONLIST_WAITS on the action that is waited for

Supported actions:
* SMART_ACTION_TALK
* SMART_ACTION_SIMPLE_TALK
* SMART_ACTION_CAST
* SMART_ACTION_SELF_CAST
* SMART_ACTION_INVOKER_CAST
* SMART_ACTION_MOVE_OFFSET
* SMART_ACTION_WP_START
* SMART_ACTION_MOVE_TO_POS
* SMART_ACTION_CROSS_CAST
* SMART_ACTION_ACTIVATE_TAXI
* SMART_ACTION_JUMP_TO_POS
* SMART_ACTION_START_CLOSEST_WAYPOINT

src/server/game/AI/SmartScripts/SmartScript.h

@@ -20,6 +20,7 @@
 
 #include "Define.h"
 #include "SmartScriptMgr.h"
+#include <memory>
 
 class AreaTrigger;
 class Creature;
@@ -32,6 +33,11 @@ class WorldObject;
 struct AreaTriggerEntry;
 struct SceneTemplate;
 
+namespace Scripting::v2
+{
+class ActionBase;
+}
+
 class TC_GAME_API SmartScript
 {
     public:
@@ -111,6 +117,7 @@ class TC_GAME_API SmartScript
         SmartAIEventList mInstallEvents;
         SmartAIEventList mTimedActionList;
         ObjectGuid mTimedActionListInvoker;
+        std::shared_ptr<Scripting::v2::ActionBase> mTimedActionWaitEvent;
         bool isProcessingTimedActionList;
         Creature* me;
         ObjectGuid meOrigGUID;