Core/Spells: Implemented summoning a personal gameobject effect (#25917)

# Conflicts:
#	src/server/game/Entities/GameObject/GameObject.cpp
#	src/server/game/Entities/GameObject/GameObject.h
#	src/server/game/Miscellaneous/SharedDefines.h
#	src/server/game/Spells/SpellInfo.cpp

src/server/game/Entities/Object/Object.cpp

@@ -1775,6 +1775,10 @@ bool WorldObject::CanSeeOrDetect(WorldObject const* obj, bool ignoreStealth, boo
                         return false;
         }
 
+        if (GameObject const* go = obj->ToGameObject())
+            if (go->IsVisibleByUnitOnly() && GetGUID() != go->GetVisibleByUnitOnly())
+                return false;
+
         if (!viewpoint)
             viewpoint = this;