Revert introduction of lightweight objects for safety

[itsmeichigo]

Part of WOOMOB-619

Description

Due to concerns about safety, this PR reverts changes made in #15774. We'll find another solution that is less error prone in a separate PR.

Testing steps

Follow the instructions in #15774 to confirm that affected areas work correctly.

Testing information

• Searched the codebase and confirmed that the concept of lightweight objects are completely gone.
• Ran the app on simulator iPhone 16 iOS 18.4 and confirmed that all the following parts work correctly:
  • Product list + product details
  • Order list + order details
  • Dashboard
  • Blaze campaign creation
  • New shipping label creation flow.

Screenshots

N/A

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• 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 in WooCommerce iOS Prototype by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS Prototype
	Build Number	30691
	Version	PR #15807
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	82fe38a
	Installation URL	10eknspcfiplg

Automatticians: You can use our internal self-serve MC tool to give yourself access to those builds if needed.

[joshheald]

Thanks! It'd be great to get those performance benefits, but I think this slower approach is better 👍