Revert "Register Django urls (#8778)"

[shuuji3]

Description

Hello, this PR reverts the PR #8778.

When I was doing the Quickstart tutorial, I was a bit confused with the urlpatterns configurations in the URLs section (https://www.django-rest-framework.org/tutorial/quickstart/#urls) because it includes URL routes for REST framework twice.

I think we don't have to append the same routes to make the REST framework routes working properly.

Here are the routes before and after this PR's change:

Before

After

As you can see, urlpatterns += router.urls makes the extra duplicated routes unnecessarily.

[auvipy]

thanks for reporting this! /a was intentionally done to show the exceptions right?

[auvipy]

I have to manually check this myself