bots: Remove unnecessary comment from test_giphy file.

This comment was added to explain the functionality of the
method called below it. Some changes in the method have led this
comment to be unnecessary.

bots/giphy/test_giphy.py

@@ -14,7 +14,7 @@ class TestGiphyBot(BotTestCase):
         bot_response = '[Click to enlarge]' \
                        '(https://media4.giphy.com/media/3o6ZtpxSZbQRRnwCKQ/giphy.gif)' \
                        '[](/static/images/interactive-bot/giphy/powered-by-giphy.png)'
-        # This message calls the `send_reply` function of BotHandlerApi
+
         with self.mock_config_info({'key': '12345678'}), \
                 self.mock_http_conversation('test_1'):
             self.initialize_bot()