Fix #22283: child pages are not moved under parent pages

[crazytonyli]

Issue

See #22283 for the issue. The issue is pretty easy to reproduce and it's my mistake that I didn't double check the app after a refactor. For context, the issue happens when a child page presents before a parent page in a pages array, which should be pretty common.

Details

When building a page tree, the elements in a pages array are processed one by one. When a child page is processed before its parent page, it is treated as an "orphan node" util it's parent page is later added to the tree. When adding the parent page to the tree, we should look up the existing orphan nodes and moving child pages under the parent page node. This logic is implemented in the relocateOrphanNodes(to:) function. However, during a refactor, I placed this function call in an incorrect place, which led to the bug in the app.

Regression Notes

1. Potential unintended areas of impact
   None.

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   Verified the issue is fixed using a test site.

3. What automated tests I added (or what prevented me from doing so)
   A couple of unit tests that can reproduce the issue.

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

UI Changes testing checklist: N/A

[peril-wordpress-mobile]

	Warnings
⚠️	This PR is assigned to a milestone which is closing in less than 4 days Please, make sure to get it merged by then or assign it to a later expiring milestone

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[mokagio]

Hey @crazytonyli 👋 You might notice a merge trunk commit here from me. That is to bring this branch up to date with the latest CI changes on trunk and ensure everything works on the new Xcode 15.1 CI stack.

Don't hesitate to ping me if there's any trouble. I hope to get to review this before the end of the day as it would be ideal to include it in 24.0

[wpmobilebot]

	1 Warning
⚠️	This PR is assigned to the milestone 24.0. This milestone is due in less than 4 days. Please make sure to get it merged by then or assign it to a milestone with a later deadline.

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[mokagio]

@crazytonyli I run this branch locally but didn't get the pages sorted hierarchically in the UI 🤔

iOS	Web

Semi-related, not all pages appear in the "Set parent" menu in the app, while they do on the web.

RPReplay_Final1704697339.MP4

[crazytonyli]

@mokagio 🤦‍♂️ My brain obviously wasn't working on my first day back.

[mokagio]

@mokagio 🤦‍♂️ My brain obviously wasn't working on my first day back.

LOL. I know the feeling 😄 🤝