[Refactor][std::string --> String] IR is updated with String (#5547)

[Refactor][std::string --> String] IR is updated with String (#5547)

* [std::string --> String] GlobalTypeVar is updated with String

* [std::string --> String] GlobalVar is updated with String

* [std::string --> String][IR] ADT is updated with String

* [std::string --> String][IR] OP is updated with String

* [std::string --> String][IR] Attrs is updated with String input

* [std::string --> String][IR] GlobalVar is updated with String

* [std::string --> String][Test] Pyconverter is updated with String change