[n7studios]

Summary

Fixes integration tests that started failing because of changes to the Kit test account and API:

• Syncs TestsTrait.php from the PHP SDK:
  • testFilterSubscribersPagination: the /v4/subscribers/filter endpoint now correctly returns has_previous_page: false and has_next_page: true when paginating back to the first page.
  • testGetSequencesPagination: no longer assumes the account has exactly 2 sequences. It now checks has_next_page against total_count.
• ResourceTest: the testRefresh* tests no longer hard-code the first and last resource names, which broke when new tags were added to the account. A new assertResourcesSorted() helper checks that resources are in the order given by order_by and order, whatever resources exist on the account.

Testing

Existing tests pass.

Checklist

• I have written a test and included it in this PR
• I have run all tests and they pass
• The code passes when running the PHP CodeSniffer
• Code meets WordPress Coding Standards for PHP, HTML, CSS and JS
• Security and Sanitization requirements have been followed
• I have assigned a reviewer or two to review this PR (if you're not sure who to assign, we can do this step for you)