don't autofill previous form fills for inputs tagged autofill="one-time-code"

[KiaraGrouwstra]

many websites nowadays use 2-factor authentication, and html inputs can now be tagged with `autofill="one-time-code"` to reflect this.

I am currently using one such a form for one-time passwords (OTP), in my case on my instance of Gitea (potentially reproducible on Codeberg).

Having enabled form filling suggestions in Firefox, when I focus such a field now Firefox suggests the previously submitted values for this field, as one would normally expect for input fields supporting autofill.

However, in the case of one-time codes (as it name implies), I feel Firefox's behavior here might be less helpful: a code that was only usable once will be unlikely to help me log in again (and if it did, then OTP wouldn't be secure).