[Composite Products] Display composite product and component hierarchy in order details

[rachelmcr]

Closes: #8963
⚠️ UI changes depend on #9778

Description

This PR adds support on the Networking layer to set the parent on an OrderItem when the item is a component in a composite product (with the Composite Products extension).

Along with the UI changes in #9778, this displays the parent/child hierarchy for a composite product and its child components in order details.

Changes

• In OrderItem, sets the parent property as either the bundled_by field (for a bundled item) or the composite_parent field (for a component).
• Adds a mock response and test to confirm the composite_parent field is parsed correctly.

Testing instructions

1. Create an order that includes a composite product.
2. In the app, open the Orders tab and select the order.
3. Confirm the composite product appears in the Products section with its components listed underneath and indented.

Screenshots

Before	After

---

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr9780-f0b72d1 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[ThomazFB]

Tested with the same scenario of the previous PR, working just fine 👍

Evidence