Downloading a non-existent backup file causes critical error

[noplanman]

When viewing the backups list and trying to download a backup that has been deleted on the target already, the popup modal where it says "Please wait..." fails in the background with the default WP error: <p>There has been a critical error on your website.</p><p><a href="https://wordpress.org/support/article/debugging-in-wordpress/">Learn more about debugging in WordPress.</a></p>

Would be nicer to say that it doesn't exist any more and offer to delete the entry, or something like that.