fix(Core/Spells): Improvements to Far Sight spell: (#11683)

* fix(Core/Spells): Improvements to Far Sight spell:

Far Sight should not interrupt while casting another spell.
Corrected setting Far Sight object as an active object.
Fixed grid activation range for active dynamic objects.
When Far Sight is over, the camera be reset to player.
Enable swapping camera between Far Sight and Sentry Totem.
Fixes #6368

* Update.

* Update.

src/server/game/Entities/DynamicObject/DynamicObject.h

@@ -50,7 +50,7 @@ public:
     void Delay(int32 delaytime);
     void SetAura(Aura* aura);
     void RemoveAura();
-    void SetCasterViewpoint();
+    void SetCasterViewpoint(bool updateViewerVisibility);
     void RemoveCasterViewpoint();
     [[nodiscard]] Unit* GetCaster() const { return _caster; }
     void BindToCaster();
@@ -60,11 +60,15 @@ public:
     [[nodiscard]] float GetRadius() const { return GetFloatValue(DYNAMICOBJECT_RADIUS); }
     [[nodiscard]] bool IsViewpoint() const { return _isViewpoint; }
 
+    ObjectGuid const& GetOldFarsightGUID() const { return _oldFarsightGUID; }
+
 protected:
     Aura* _aura;
     Aura* _removedAura;
     Unit* _caster;
     int32 _duration; // for non-aura dynobjects
     bool _isViewpoint;
+    uint32 _updateViewerVisibilityTimer;
+    ObjectGuid _oldFarsightGUID;
 };
 #endif