Changes to API docs for 2024.3 release

[ktuite]

Closes #1211

This PR

• adds 2 missing form actions (form.update.draft.replace and upgrade.process.form.entities_version)
  • the other place in this release that we added new actions (for the submission backlog) already have these actions mentioned in the API docs.
• adds the user preferences endpoint to the changelog and removes some extra auth headers in the examples for those endpoints
• adds the file attachment hash to the form attachment endpoint with a little bit of explainer text and changing the example responses to be more consistent

What has been done to verify that this works as intended?

Why is this the best possible solution? Were any other approaches considered?

How does this change affect users? Describe intentional changes to behavior and behavior that could have accidentally been affected by code changes. In other words, what are the regression risks?

Does this change require updates to the API documentation? If so, please update docs/api.yaml as part of this PR.

Before submitting this PR, please make sure you have:

• run make test and confirmed all checks still pass OR confirm CircleCI build passes
• verified that any code from external sources are properly credited in comments or that everything is internally sourced