Remove broken Xdebug enable

While this works, it applies to all PHP versions in the matrix, including those that don't have Xdebug. Additionally, it does not produce the desired coverage report , so it isn't serving the intended purpose.

plugins/templates/before-script.yml

@@ -14,7 +14,3 @@ before_script:
 
   # PHPUnit requirements
   - composer global require yoast/phpunit-polyfills
-
-  # Enable Xdebug for coverage reports
-  - echo "zend_extension=xdebug.so" > /usr/local/etc/php/conf.d/xdebug.ini
-  - echo "xdebug.mode=coverage" >> /usr/local/etc/php/conf.d/xdebug.ini