Update test to check if you're really talking to a mongos

Author: estolfo

spec/mongo/collection/view_spec.rb

@@ -369,7 +369,7 @@
         end
       end
 
-      context 'when the cluster is sharded' do
+      context 'when the cluster is sharded', if: sharded? do
 
         before do
           allow(authorized_collection.cluster).to receive(:sharded?).and_return(true)