Docs: Add Duo Add-On requirements for context exclusion feature

What does this MR do and why?

Closes #576002 to update this docs page

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Related to #576002