MT#8491 Fix subscriber termination via API.

1.Provisioning_voip_subscribers may be already deleted during termination.
2.Return issue already fixed in master, seems like not integrated in 3.3.

lib/NGCP/Panel/Role/API/Subscribers.pm

@@ -595,7 +595,10 @@ sub update_item {
     my $old_profile = $prov_subscriber->profile_id;
 
     $subscriber->update($billing_res);
-    $subscriber->provisioning_voip_subscriber->update($provisioning_res);
+    #Can be deleted during termination, maybe others
+    if($subscriber->provisioning_voip_subscriber->in_storage){
+        $subscriber->provisioning_voip_subscriber->update($provisioning_res);
+    }
     $subscriber->discard_changes;
 
     if(($prov_subscriber->profile_id // 0) != ($old_profile // 0)) {

lib/NGCP/Panel/Utils/Subscriber.pm

@@ -348,7 +348,7 @@ sub update_preferences {
     foreach my $k(keys %{ $preferences } ) {
         my $pref = NGCP::Panel::Utils::Preferences::get_usr_preference_rs(
             c => $c, attribute => $k, prov_subscriber => $prov_subscriber);
-        if($pref->first && $pref->first->attribute->max_occur == 1) {
+        if($pref && $pref->first && $pref->first->attribute->max_occur == 1) {
             unless(defined $preferences->{$k}) {
                 $pref->first->delete;
             } else {