Improve the validation process when changing the product type

[mdperez86]

Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

Closes #43280

How to test the changes in this Pull Request:

Using the WooCommerce Testing Instructions Guide, include your detailed testing instructions:

1. Make sure feature New product editor is enabled under /wp-admin/admin.php?page=wc-settings&tab=advanced&section=features
2. Go to Products -> Add new from the left side menu.
3. Under the General tab a description This is a standard product. Change product type should be shown below the Basic details section.
4. When clicking the Change product type a dropdown menu should be shown listing all the available product types.

6. From the list the Standard product should be highlighted in blue.
7. When selecting the Affiliate product from the list and error should be shown highlighting the NAME field in red.
8. Fill the NAME field and then select the Affiliate product from the list again.
9. The change should be applied successfully. (The product now should be of type external)
10. Clicking the Standard product again should be done without showing any error.

Changelog entry

• Automatically create a changelog entry from the details below.

Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

Message

Comment

[github-actions]

Hi @octaedro,

Apart from reviewing the code changes, please make sure to review the testing instructions as well.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions

[github-actions]

Test Results Summary

Commit SHA: 9d41ffc

Test 🧪	Passed ✅	Failed 🚨	Broken 🚧	Skipped ⏭️	Unknown ❔	Total 📊	Duration ⏱️
API Tests	259	0	0	2	0	261	0m 37s
E2E Tests	249	0	0	30	0	279	3m 42s

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To view the full API test report, click here.
To view the full E2E test report, click here.
To view all test reports, visit the WooCommerce Test Reports Dashboard.

[octaedro]

The validation for the external product link is not there anymore (mimicking the legacy experience).
This PR LGTM 🚀