ECWID-161269 - set default value

Author: ArAkAru

src/main/kotlin/com/ecwid/apiclient/v3/ApiClientHelper.kt

@@ -40,7 +40,7 @@ private val REQUEST_ID_CHARACTERS = ('a'..'z') + ('A'..'Z') + ('0'..'9')
 
 class ApiClientHelper private constructor(
 	private val apiServerDomain: ApiServerDomain,
-	private val credentials: ApiCredentials?,
+	private val credentials: ApiCredentials? = null,
 	private val loggingSettings: LoggingSettings,
 	val httpTransport: HttpTransport,
 	val jsonTransformer: JsonTransformer,