Fix File Download API when Guestbook at request is true

[qqmyers]

What this PR does / why we need it: #12110 changed the GET /api/access/datafile/{id} and related to require submission of a guestbook response id when a guestbook is enabled on the dataset. This breaks the API calls when guestbook-at-request is true for a dataset - they return an incorrect 400 response.

Which issue(s) this PR closes:

• Closes #

Special notes for your reviewer: This PR just adds a check to not require a gbrids check if GB at request is true. One could argue that a gbrids could still be required but

• while /api/access/datafile/{id}/requestAccess now accepts a gb response, it does not return the id
• presumably requestAccess would have failed/access not granted if the gb response doesn't exist
• the time-based check would have to be revised as the access request could have been far in the past

Suggestions on how to test this: Manually one can publish a restricted file, in a dataset with a guestbook and gb at request on, and then try a previewer on it. The separate page preview view will fail with a 400 response on the file access request before this PR.
I would have expected this test to be for this case, but it appears to require another guestbook response to be entered at download as well - seems like accepting a gb response in a download request should also fail when gb at request is true (another bug/aspect of this bug).

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

Is there a release notes update needed for this change?:

Additional documentation: