formulary: allow for more keyless fields when loading from API

[apainintheneck]

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same change?
• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes? Here's an example.
• Have you successfully run brew style with your changes locally?
• Have you successfully run brew typecheck with your changes locally?
• Have you successfully run brew tests with your changes locally?

---

These were fields I missed the first time around in #16420. Now the values should line up with the expected values.

I checked it with apainintheneck/homebrew-dev-utils#36 and a new branch I'm working on locally based on #16433 (comment).

[apainintheneck]

Looks like there is an unrelated docs generation error.

[MikeMcQuaid]

Thanks @apainintheneck, makes sense!