remove thank you for creating with WP in the admin css

admin css

<?php
/*
*Add this snipt to functions.php file. Also add a wp-admin.css file to the child theme.
*
*?
function load_jmg_wp_admin_style(){
    wp_register_style( 'jmg_wp_admin_css', get_bloginfo('stylesheet_directory') . '/wp-admin.css', false, '1.0.0' );
    wp_enqueue_style( 'jmg_wp_admin_css' );
}
add_action('admin_enqueue_scripts', 'load_jmg_wp_admin_style');