wpcept: Fully disable update checks

[JDGrimes]

Right now we attempt to disable the core/plugin/theme update checks in WordPress when running Codeception acceptance tests, because these cause a request to be made to WordPress.org, which is just a waste of time and resources.

However, while doing local testing, I've come to the conclusion that we may not actually be fully disabling at least the plugin and theme updates. It's possible that we aren't disabling the core updates entirely either, although I can't see how.

Anyway, I think that maybe we should add something like this to the disable update checks method, although we should do some more investigation to be sure:

            if ( 'update_themes' === $transient ) {

                $themes = wp_get_themes();

                foreach ( $themes as $theme ) {

                    $stylesheet = $theme->get_stylesheet();

                    $array['response'][ $stylesheet ] = array();
                    $array['checked'][ $stylesheet ]  = $theme->get( 'Version' );
                }
            }

            if ( 'update_plugins' === $transient ) {

                $plugins = get_plugins();

                foreach ( $plugins as $file => $plugin ) {
                    $array['response'][ $file ] = array();
                    $array['checked'][ $file ] = $plugin['Version'];
                }
            }