Adjust --datagrepper-url name in test_cli

Signed-off-by: freedisch <freeproduc@gmail.com>

tests/unit/test_cli.py

@@ -804,7 +804,7 @@ def test_successful_message_replay(self, mock_publish, mock_get_message):
         mock_get_message.return_value = message_data
 
         result = self.runner.invoke(
-            cli.replay, [message_id, f"--datagrepper_url={datagrepper_url}"]
+            cli.replay, [message_id, f"--datagrepper-url={datagrepper_url}"]
         )
 
         assert (