Add custom taxonomy to admin emails

I am able to display my custom taxonomy on order emails but the problem is that it’s showing up on customer emails, which I don’t want.

How do I add my custom taxonomy to admin emails but not customer emails using just hooks and filters?

I am using the hooks found in email-order-items.php but I don’t see a way to check for $sent_to_admin?

Here is the code I am using: https://gist.github.com/pauldowlin/ffbff08be311e1c5fc52ec02891f71e4

Thanks for any help on this.