As a barista, I often get customers who express this same kind of sentiment; feeling bad for "ruining" latte art by drinking it.
Y'all realize we know latte art is temporary, right? 😅 It's honestly one of my favourite aspects of latte art. It doesn't change the taste of the drink, it'll last 5 minutes at best (even if no one drinks it, it doesn't take long for latte art to look kinda gross if left on the counter). Yet baristas all over take the little extra effort to make a drink look pretty, just for a moment.
Seriously, you shouldn't feel bad, if anything baristas will be hyped that you appreciate our artwork!