I just had the same issue and accidentally licensed a template on my work account, please can you help? The template ID is #120193529, it would be really great if we could remove licensed content or at least as one user said above, a two-click system (I have found myself nearly licensing content a lot because I intend to preview it or save for later, this time it caught me out!).
I apologize for the troubles faced by you.
I did check the file ID as provided by you and it appears to be a free template for which you haven't been charged anything.
As there is noway of unlicensing the file that you've licensed once, you may go ahead not use the template.