[git_cl_test] Fix test mocking for git_auth.AutoConfigure

Bug: 404613530
Change-Id: I307637ccd5ac5e59ca13588572dd0cb0bf691d03
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/6431247
Reviewed-by: Yiwei Zhang <yiwzhang@google.com>
Commit-Queue: Allen Li <ayatane@chromium.org>

tests/git_cl_test.py

@@ -2448,6 +2448,7 @@ class TestGitCl(unittest.TestCase):
         mock.patch(
             'git_cl.gerrit_util.CookiesAuthenticator',
             CookiesAuthenticatorMockFactory(hosts_with_creds=auth)).start()
+        mock.patch('git_auth.AutoConfigure', return_value=None).start()
         scm.GIT.SetConfig('', 'remote.origin.url',
                           'https://chromium.googlesource.com/my/repo')
         cl = git_cl.Changelist()