Remove unused `$current_site` global in MS Sites list table

Found itself unused after [32719].

See #32434.


git-svn-id: https://develop.svn.wordpress.org/trunk@33097 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-ms-sites-list-table.php

@@ -484,8 +484,6 @@ class WP_MS_Sites_List_Table extends WP_List_Table {
 	 * @return string Row actions output.
 	 */
 	protected function handle_row_actions( $blog, $column_name, $primary ) {
-		global $current_site;
-
 		if ( $primary === $column_name ) {
 			$blogname = untrailingslashit( $blog['domain'] . $blog['path'] );