Add blog meta on WordPress multisite

mu-blog-settings.php

<?php
class WeAreWP_Add_Blog_Order {
    public static function init() {
        $class = __CLASS__ ;
        if ( empty( $GLOBALS[ $class ] ) )
            $GLOBALS[ $class ] = new $class;
    }
    public function __construct() {
        add_filter( 'wpmu_blogs_columns', array( $this, 'get_id' ) );
        add_action( 'manage_sites_custom_column', array( $this, 'add_columns' ), 10, 2 );
        add_action( 'manage_blogs_custom_column', array( $this, 'add_columns' ), 10, 2 );
        add_action( 'admin_footer', array( $this, 'add_style' ) );
    }
    public function add_columns( $column_name, $blog_id ) {
        if ( 'blog_id' === $column_name ){
            echo $blog_id;
            //render column value
        }elseif( 'order' === $column_name ){
            echo get_site_meta($blog_id, 'blog_order', true );
        }
        return $column_name;
    }
    // Add in a column header
    public function get_id( $columns ) {
        $columns['blog_id'] = __('ID');
        //add extra header to table
        $columns['order'] = __('Order');

        return $columns;
    }
    public function add_style() {
        echo '<style>#blog_id { width:7%; }</style>';
    }
}
add_action( 'init', array( 'WeAreWP_Add_Blog_Order', 'init' ) );



function wearewp_custom_network_site_info_field() {
	
	submit_button( 'Save Changes', 'primary', 'primary-save', true, "" ); 
	echo "</form>"; // Close form in site-info.php

	$blogid = isset( $_REQUEST['id'] ) ? (int) $_REQUEST['id'] : 0;	
	$meta_key = 'blog_order';
		
	$saved_custom_field = get_site_meta( $blogid, $meta_key, true );
	
	if ( isset( $_REQUEST['action'] ) && 'update-site-custom' === $_REQUEST['action'] ) {
		if ( isset( $_POST[$meta_key] ) && isset( $saved_custom_field ) ) {
			update_site_meta( $blogid, $meta_key, $_POST[$meta_key], false );
		} else if ( isset( $_POST[$meta_key] ) ) {
			add_site_meta( $blogid, $meta_key, $_POST[$meta_key], false );
		}
			
		$url =	add_query_arg(
			array(
				'update' => 'updated',
				'id'     => $blogid,
			),
			'site-info.php'
		);
			
		echo("<script>location.href = '".$url."'</script>");
	}
	
	$blog_order = get_site_meta( $blogid, $meta_key, true );
	
	?>
	 <hr><h3>Custom Fields</h3>
	 <form method="post" action="site-info.php?action=update-site-custom">
		 <table>
			 <tr>
				 <td>
					<?php wp_nonce_field( 'edit-site' ); ?>
					<input type="hidden" name="id" value="<?php echo esc_attr( $blogid ); ?>" />
					<table class="form-table" role="presentation"><tr class="form-field">
							<th scope="row"><label for="blog_order"><?php _e( 'Order' ); ?></label></th>
							<td><input name="blog_order" type="text" id="blog_order" value="<?php echo esc_attr( $blog_order ); ?>"></td>
						</tr></table>
			 	</td>
			 	<td><?php submit_button( 'Save Changes', 'secondary', 'custom-save', true, "" ); ?></td>
			 </tr>
		 </table>
		 
		 <style>
			 .submit .button { display: none; }
			 #custom-save, #primary-save { display: block; }
		 </style>
			
  <?php
}
add_action( 'network_site_info_form', 'wearewp_custom_network_site_info_field', 10, 0 );