MWPW-162914 [nala][MEP]Nested placeholder issues

[jpratt2]

This nala test addresses issues with nested placeholders: they should be accessible in a separate manifest and the most recent placeholder should replace the previous one.

Resolves: MWPW-162914

Test URLs:

Before: https://main--milo--adobecom.aem.page/?martech=off
After: https://nested-placeholder--milo--adobecom.aem.page/?martech=off
PSI check: https://nested-placeholder--milo--adobecom.aem.page/?martech=off
test page with examples: https://main--milo--adobecom.hlx.page/drafts/nala/features/personalization/nested-placeholder/

[aem-code-sync]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed.
In case there are problems, just click a checkbox below to rerun the respective action.

• Re-run PSI checks
• Re-sync branch

Commits

• b38a120 ✅ (latest)
• 1f215fc ✅

[aem-code-sync]

	Page	Scores	Audits	Google
📱	/?martech=off
🖥️	/?martech=off

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.46%. Comparing base (82694a3) to head (b38a120).

Additional details and impacted files

@@           Coverage Diff           @@
##            stage    #3244   +/-   ##
=======================================
  Coverage   96.46%   96.46%           
=======================================
  Files         255      255           
  Lines       59363    59363           
=======================================
  Hits        57266    57266           
  Misses       2097     2097           

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[github-actions]

This pull request is not passing all required checks. Please see this discussion for information on how to get all checks passing. Inconsistent checks can be manually retried. If a test absolutely can not pass for a good reason, please add a comment with an explanation to the PR.

[github-actions]

This PR has not been updated recently and will be closed in 7 days if no action is taken. Please ensure all checks are passing, https://github.com/orgs/adobecom/discussions/997 provides instructions. If the PR is ready to be merged, please mark it with the "Ready for Stage" label.

[jpratt2]

I am closing this PR because there is an outstanding issue: https://jira.corp.adobe.com/browse/MWPW-162760
When that MWPW ticket is closed, I will re-open a new PR

[jpratt2]

I need to re-open this pull request. I closed it incorrectly. I said that this outstanding issue was involved: "I am closing this PR because there is an outstanding issue: https://jira.corp.adobe.com/browse/MWPW-162760 "
It turns out that this issue is not related.
(It is only related to #2976)

[jpratt2]

@skumar09 when you have a minute, for your review