chore: fix swagger docs for consistency pref

[jimmyjames]

Updates the documentation for the consistency parameter.

Description

• Adds a description about the consistency endpoints to the Check and ListObjects API descriptions, and an example for Check.
• Overrides the example usage showing UNSPECIFIED to show MINIMIZE_LATENCY instead.

References

Fixes #189

Review Checklist

• I have clicked on "allow edits by maintainers".
• I have added documentation for new/changed functionality in this PR or in a PR to openfga.dev [Provide a link to any relevant PRs in the references section above]
• The correct base branch is being used, if not main
• I have added tests to validate that the change in functionality is working as expected