Fix pypi token keyrinerror (#5189) (#5911)

* add checking for env variable in pypi token getter

* add unit tests for env pypi token

* add checking for env variable in pypi token getter

* add unit tests for env pypi token

* add info to the changelog

* refactor the structure

* fix unit tests

* undo changelog addition

* change docstring format to sphinx

* delete uncrsy unit test

* Delete unscry funtion call

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>

* Update src/poetry/utils/password_manager.py

Co-authored-by: Bartosz Sokorski <b.sokorski@gmail.com>

* fix unit tests

* lol

* fix type hints

Co-authored-by: Bjorn Neergaard <bjorn@neersighted.com>
Co-authored-by: Bartosz Sokorski <b.sokorski@gmail.com>