Remove unnecessary if statement.

$response is of type Psr\Http\Message\ResponseInterface, thus it always evaluated to true

Author: mvdnbrk

src/Client.php

@@ -131,10 +131,6 @@ public function performHttpCall(string $httpMethod, string $apiMethod, ?string $
             throw DhlParcelException::createFromGuzzleRequestException($e);
         }
 
-        if (! $response) {
-            throw new DhlParcelException('No API response received.');
-        }
-
         return $response;
     }