MT#65579 do not set primary_number undef in shared resource_from_item

Keep missing primary numbers absent from the shared helper so provisioning
template update paths do not treat them as an explicit clear. Also fix
perlcritic mixed boolean operators.

NGCP-Flow: mr26.0

Change-Id: Ib5ef634e7a9e65678ec872d71d65aea8301fc364

lib/NGCP/Panel/Utils/Subscriber.pm

@@ -287,8 +287,6 @@ sub resource_from_item {
         $resource{primary_number}->{ac} = $item->primary_number->ac;
         $resource{primary_number}->{sn} = $item->primary_number->sn;
         $resource{primary_number}->{number_id} = int($item->primary_number->id);
-    } else {
-        $resource{primary_number} = undef;
     }
 
     my @aliases = ();