Fix Failing Tests

[n7studios]

Summary

Fixes WPUnit tests, which have not run since this PR in August 2023, which split the test groups from acceptance/broadcast to acceptance/broadcasts/blocks-shortcodes and acceptance/broadcasts/import-export. As there's no acceptance/broadcasts test group, WPUnit tests never ran.

Fixes category and form tests failing due to using the incorrect convertkit.com, and a landing page test that was failing due to the introduction of the HTML lang attribute. These tests previously passed, so unsure if changes have been made on the Kit API / app or a migration run to switch over any errant convertkit.com references in forms.

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)