Add a built-in app to Fire Kids profile?

I have a bunch of Fire tablets for my kids and we are using the FreeTime locked profiles for them. I can download 3rd-party apps and then share them on my kids profiles. But I can't do this with the built-in apps, like Clock. Do you know how I can do this? I've chatted with Amazon support and they were no help. Here are the Amazon instructions for more details on how this works for 3rd-party apps: https://www.amazon.com/gp/help/customer/display.html?nodeId=202119930