Fix: CORS issues in third-party auth disconnect by adding JSON endpoint (#37100)

Add a json auth endpoint where previously there was only an HTML redirect version. This will make it easier to work with MFEs.

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Co-authored-by: Feanil Patel <feanil@axim.org>

common/djangoapps/third_party_auth/api/tests/test_views.py

@@ -419,7 +419,7 @@ class TestThirdPartyAuthUserStatusView(ThirdPartyAuthTestMixin, APITestCase):
         assert (response.data ==
                [{
                    'accepts_logins': True, 'name': 'Google',
-                   'disconnect_url': '/auth/disconnect/google-oauth2/?',
+                   'disconnect_url': '/auth/disconnect_json/google-oauth2/?',
                    'connect_url': f'/auth/login/google-oauth2/?auth_entry=account_settings&next={next_url}',
                    'connected': False, 'id': 'oa2-google-oauth2'
                }])