logging: Remove unnecessary mock.patch() for logging.

Our test-backend validation confirms that we don't log anything to
stdout in the tests, so the fact that CI passes with this removes
shows there was nothing being logged.

zerver/tests/test_email_log.py

@@ -32,8 +32,7 @@ class EmailLogTest(ZulipTestCase):
 
         self.assertEqual(get_forward_address(), forward_address)
 
-        with self.settings(EMAIL_BACKEND='zproject.email_backends.EmailLogBackEnd'), \
-                mock.patch('logging.info', return_value=None):
+        with self.settings(EMAIL_BACKEND='zproject.email_backends.EmailLogBackEnd'):
             with mock.patch('zproject.email_backends.EmailLogBackEnd.send_email_smtp'):
                 result = self.client_get('/emails/generate/')
                 self.assertEqual(result.status_code, 302)

zerver/tests/test_user_groups.py

@@ -422,7 +422,6 @@ class UserGroupAPITestCase(ZulipTestCase):
             content=content_with_group_mention,
         )
 
-        with mock.patch('logging.info'):
         result = self.api_post(sender, "/json/messages", payload)
 
         self.assert_json_success(result)