PR enhancing AAL, IAL, and FAL constraints

[Rene2mt]

Committer Notes

This PR addresses #812 (comment), ensuring that an SSP has exactly one authentication-assurance-level property, one identity-assurance-level property, and one federation-assurance-level property. The PR includes minor changes to constraints has-authentication-assurance-level, has-identity-assurance-level, and has-federation-assurance-level.

All Submissions:

• Have you selected the correct base branch per Contributing guidance?
• Have you set "Allow edits and access to secrets by maintainers"?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• Have you squashed any non-relevant commits and commit messages? [instructions]
• Have you added an explanation of what your changes do and why you'd like us to include them?
• If applicable, have all FedRAMP Documents Related to OSCAL Adoption affected by the changes in this issue have been updated.?
• If applicable, does this PR reference the issue it addresses and explain how it addresses the issue?

By submitting a pull request, you are agreeing to provide this contribution under the CC0 1.0 Universal public domain dedication.

[Gabeblis]

LGTM!