Multisite: Use correct types in get_sites() during network upgrade.

`spam`, `deleted`, and `archived` query args should be integers, not strings.

Props ocean90.
See #37823.


git-svn-id: https://develop.svn.wordpress.org/trunk@38819 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/network/upgrade.php

@@ -53,9 +53,9 @@ switch ( $action ) {
 		}
 
 		$site_ids = get_sites( array(
-			'spam'       => '0',
-			'deleted'    => '0',
-			'archived'   => '0',
+			'spam'       => 0,
+			'deleted'    => 0,
+			'archived'   => 0,
 			'network_id' => get_current_network_id(),
 			'number'     => 5,
 			'offset'     => $n,