There is a general issue with consistency when defining the redirect URL between using localhost and 127.0.0.1. This is true for edxapp and ecommerce.
For this specific proposed change, I got the systems communicating correctly by changing the Redirect URL to http://127.0.0.1:8002/complete/edx-oidc/ on my devstack instance (no https).
without this change I received the error, "The requested redirect didn't match the client settings." when rendering page: http://127.0.0.1:8000/oauth2/authorize/confirm
traced back to file venvs/edxapp/src/django-oauth2-provider/provider/oauth2/forms.py where is does a string compare of the two configured redirect uris here:
if not redirect_uri == self.client.redirect_uri: @line 167.