Changes proposed in this Pull Request:

Follow-up to #32941.

• Rename functions to be more consistent
• Move out experiment codes to onboarding package so it can be used by the package
• Add ExPlat call for PHP part of product task experiment
• Add experiment check for product import
• Add experiment check for trackView

How to test the changes in this Pull Request:

Prerequisite

1. Install WooCommerce Admin Test Helper
2. Go to Tools > WCA Test Helper > Features
3. Enable experimental-products-task
4. Make sure your site has woocommerce_allow_tracking option set to yes

Testing old import if not treatment

1. Install WooCommerce Admin Test Helper
2. Go to Tools > WCA Test Helper > Experiments
3. Disable both woocommerce_products_task_layout_stacked and woocommerce_products_task_layout_card for both frontend and backend experiment
4. Make sure there are no products in store (if there are in trash, empty them)
5. Go to appearance task /wp-admin/admin.php?page=wc-admin&task=appearance
6. Click on "Import products" button
7. Go to Products page
8. Observe 18 products are imported

Testing import under treatment

1. Enable treatment for either woocommerce_products_task_layout_stacked or woocommerce_products_task_layout_card for backend and frontend
2. Trash all products & empty trash
3. Go to Products task
4. Click on "Load sample products"
5. Observe 9 products are imported

Testing trackView

1. Enable treatment for either woocommerce_products_task_layout_stacked or woocommerce_products_task_layout_card for frontend
2. Open up developer console and make sure tracks are debugged localStorage.setItem( 'debug', 'wc-admin:*' );
3. Go to Products task
4. Observe wcadmin_task_view track in developer console with experimental_products: true prop

Other information:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you written new tests for your changes, as applicable?
• Have you successfully run tests with your changes locally?
• Have you created a changelog file for each project being changed, ie pnpm nx changelog <project>?

FOR PR REVIEWER ONLY:

• I have reviewed that everything is sanitized/escaped appropriately for any SQL or XSS injection possibilities. I made sure Linting is not ignored or disabled.