Add sync and usage flags to legacy features.

[vedanshujain]

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:

Add the sync and custom table usage enabled flag to legacy so that it does not generate warnings when no compatibility is declared explicitly. The compatibility is taken cared by the custom_order_tables flag and so checking for these new feature flags is not required.

How to test the changes in this Pull Request:

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

1. Check out trunk.
2. Enable a plugin that has declared compatibility with HPOS. For example, the WooCommerce Stripe gateway.
3. You should be seeing the incompatibility warning on all admin screens:
   
4. Go to wp-admin/plugins.php?plugin_status=incompatible_with_feature and confirm that the Stripe gateway is listed as incompatible (despite it being compatible). In particular, you'll see that it is listed as incompatible with COT but also a '' feature:
   
5. Check out this branch and refresh the page.
6. The warning should now be gone.
7. The list of plugins on wp-admin/plugins.php?plugin_status=incompatible_with_feature should no longer indicate that Stripe is incompatible with COT.

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]

Test Results Summary

Commit SHA: ebe26b7

Test 🧪	Passed ✅	Failed 🚨	Broken 🚧	Skipped ⏭️	Unknown ❔	Total 📊	Duration ⏱️
API Tests	259	0	0	2	0	261	1m 8s
E2E Tests	189	0	0	19	0	208	18m 27s

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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.

[github-actions]

Hi @jorgeatorres,

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

[jorgeatorres]

FWIW, I've expanded the testing instructions above to add a more clear picture of what's happening.

[jorgeatorres]

LGTM. I've tested that the warning appears on trunk for Stripe (despite its declaration of compatibility) and that updating to this branch makes the warning go away.

Also tested that enabling/disabling HPOS from the WC > Settings > Advanced > Features screen works correctly.