[ms] Fix the account setup handling for multisites with only one site. (#856)

* [version] Bump version to 2.13.1 and pricing app to 1.3.1.

* [ms] Fix the account setup handling for multisites with only one site.

Author: fajardoleo

assets/js/pricing/freemius-pricing.js

@@ -17432,7 +17432,7 @@ function setup_network_account(
                 FS_User_Lock::instance()->unlock();
             }
 
-            if ( 1 < count( $installs ) ) {
+            if ( 1 < count( $installs ) || fs_is_network_admin() ) {
                 // Only network level opt-in can have more than one install.
                 $is_network_level_opt_in = true;
             }