Add trademark for-use regression test

[GeorgeWebDevCy]

Summary

• Add a regression fixture for the plugin name reported in trademark check should allow "for" anywhere not only at end #977: Do Something for WooCommerce and Xyz.
• Confirm that for WooCommerce is accepted when it appears in the middle of the plugin name.
• Keep existing duplicate trademark coverage intact through the current bad-case fixture.

Fixes #977.

Testing

• php -l tests/phpunit/tests/Checker/Checks/Trademarks_Check_Tests.php
• php -l tests/phpunit/testdata/plugins/test-trademarks-plugin-header-for-woocommerce-middle/load.php
• vendor/bin/phpcs --standard=phpcs.xml.dist tests/phpunit/tests/Checker/Checks/Trademarks_Check_Tests.php tests/phpunit/testdata/plugins/test-trademarks-plugin-header-for-woocommerce-middle/load.php
• PHP 8.4 Docker harness against validate_name_has_no_trademarks(): issue example allowed; duplicate WooCommerce case still rejected.

[github-actions]

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Co-authored-by: GeorgeWebDevCy <orionaselite@git.wordpress.org>
Co-authored-by: swissspidy <swissspidy@git.wordpress.org>
Co-authored-by: kkmuffme <kkmuffme@git.wordpress.org>

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