[Fix] Register optimizer constructor with mmseg (#1456)

* [fix] register optimizer onstructor with mmseg

* fix lint

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* fix

* Update tests/test_core/test_optimizer.py

* Update tests/test_core/test_optimizer.py

* Update tests/test_core/test_optimizer.py

* Update tests/test_core/test_optimizer.py

* fix lint

Co-authored-by: Miao Zheng <76149310+MeowZheng@users.noreply.github.com>