Default WP_List_Table Styles Rules for UI Improvement

Since `TGMPA_List_Table` is hijacking and extending `WP_List_Table` which is private class and is Limited for core usage only. Similary, we are utilizing similar plural args of `WP_Plugins_List_Table`  too. Means we are adding plugins page style rules directly from the core plugins page and our table `<thead> and <tfoot>` checkbox are not well managed as well as other css stuffs. Thus let's be smart and accept default `WP_List_Table` styles rather than Plugins Page. 
```php
/**
 * Confidential Information!
 * WP_Plugins_List_Table is already utilizing 'plural' => 'plugins'
 * Let's be smart dudes and use only singular args :)
 */
parent::__construct( array(
	'plural' => 'plugins',
	'screen' => isset( $args['screen'] ) ? $args['screen'] : null,
) );
```