refactor: remove operator< from Property

include/reflection/property.h

@@ -39,11 +39,6 @@ public:
   
   auto begin() const { return path_.begin(); }
   auto end() const { return path_.end(); }
-  
-protected:
-  friend bool operator<(Property const &lhs, Property const &rhs) {
-    return lhs.path_ < rhs.path_;
-  }
 };
 
 }