I completely removed this file over 7 months ago.
Anyway, for anyone with a similar issue and stumbles upon this thread, here's an article that might be helpful: https://support.squarespace.com/hc/en-us/articles/205812748-Image-and-file-URLs-in-Squarespace?platform=v6&websiteId=6371a73535aaac2541dbeee2
Towards the bottom it has some information about requesting a static URL removal.