fixed bug when using deprecated client builder methods without ssl

Author: transistive

src/ClientBuilder.php

@@ -107,7 +107,7 @@ public function addBoltConnection(string $alias, string $url, BoltConfiguration
         $parsedUrl = Uri::create($url);
         $options = $config->getSslContextOptions();
         $postScheme = '';
-        if ($options !== []) {
+        if ($options && $options !== []) {
             if (($options['allow_self_signed'] ?? false) === true) {
                 $postScheme = '+ssc';
             } else {