Add check for replica set

Author: levon80999

tests/Operation/FindAndModifyFunctionalTest.php

@@ -5,7 +5,6 @@
 use MongoDB\Driver\BulkWrite;
 use MongoDB\Driver\Exception\CommandException;
 use MongoDB\Driver\ReadPreference;
-use MongoDB\Driver\Server;
 use MongoDB\Driver\WriteConcern;
 use MongoDB\Exception\UnsupportedException;
 use MongoDB\Model\BSONDocument;