Prior to this change, after creating a site, the network site count was always refreshed on the current network, regardless of whether the site was created on a different network. With the recent changes, particularly [40591], it is now possible to update the site count for a specific `$network_id`, so this changeset makes use of the new parameter.
Fixes#38699.
git-svn-id: https://develop.svn.wordpress.org/trunk@40612 602fd350-edb4-49c9-b593-d223f7449a82