update nested landmarks and test cases

[shunguoy]

Summary

• New or modified checker rule(s)
• New or modified help files
• Simulator updates
• Extension UI changes
• Automated tool changes
• Other (Provide information)

This PR is related to the following issue(s):

• Fixes ace.js polyfills unconditionally assign to String/Array prototypes — crashes on pages that freeze built-ins #2579
• Fixes [BUG]: aria_article_label_unique firing when articles are nested #2580

Testing reference:

• test/v2/checker/accessibility/rules/aria_article_label_unique_ruleunit/article_nested.html
• https://ibmdocs-test.dcs.ibm.com/docs/en/cno?topic=configure-shortcuts

I have conducted the following for this PR:

• I validated this fix in my local env and provided testing information above
• I understand that the title of this PR will be used for the next release notes.
• I added I agree to the DCO at https://developercertificate.org/ for this contribution. as a comment after creating the pull request.

Assets to aide review attached

• Links to design artifacts
• Links to video walkthrough of user experience
• Other

Definition of Done

• Peer review complete
• Secondary review complete
• Staging deployment verified