Ignore empty redis username string in PhpRedisConnector (#41773)

* Ignore empty redis username string

* Revert code format change

Author: seanmtaylor

src/Illuminate/Redis/Connectors/PhpRedisConnector.php

@@ -84,7 +84,7 @@ protected function createClient(array $config)
             $this->establishConnection($client, $config);
 
             if (! empty($config['password'])) {
-                if (isset($config['username']) && is_string($config['password'])) {
+                if (isset($config['username']) && $config['username'] !== '' && is_string($config['password'])) {
                     $client->auth([$config['username'], $config['password']]);
                 } else {
                     $client->auth($config['password']);