Core/Vmaps: Fixed getting map height near large gameobjects like LK platform

Updates #19865

(cherry picked from commit cfb0f9fb19)

src/common/Collision/DynamicTree.cpp

@@ -91,7 +91,7 @@ struct DynTreeImpl : public ParentTree/*, public Intersectable*/
 
     void update(uint32 difftime)
     {
-        if (!size())
+        if (empty())
             return;
 
         rebalance_timer.Update(difftime);
@@ -134,11 +134,6 @@ void DynamicMapTree::balance()
     impl->balance();
 }
 
-int DynamicMapTree::size() const
-{
-    return impl->size();
-}
-
 void DynamicMapTree::update(uint32 t_diff)
 {
     impl->update(t_diff);