Show Template text in buttom card

Configuration Frontend
1

I cant figure this out… how do i get the below template text to show in the name of a button card?

{{ (strptime(state_attr("calendar.birthdays", "start_time"), '%Y-%m-%d %H:%M:%S', today_at()) | as_local - today_at()).days }} Days until {{ state_attr("calendar.birthdays", "message") }}
2

Based on the Button Card configuration schema from the docs there are no keys that accept templates as values.