Fix type hints in jwst code

[stscijgbot-jp]

Issue JP-3749 was created on JIRA by Melanie Clarke:

Typing hints in extract.py are out of date and need to be either updated or removed.

We should also consider adding a mypy check to CI for the jwst repo, to verify that any included typing hints are correct and up to date.  The stcal repo already performs a similar check.