Container::addHidden Allow any type so it works same as setDefaultValue (#245)

Author: dakorpar

src/Forms/Container.php

@@ -329,7 +329,7 @@ public function addMultiUpload(string $name, $label = null): Controls\UploadCont
 	/**
 	 * Adds hidden form control used to store a non-displayed value.
 	 */
-	public function addHidden(string $name, string $default = null): Controls\HiddenField
+	public function addHidden(string $name, $default = null): Controls\HiddenField
 	{
 		return $this[$name] = (new Controls\HiddenField)
 			->setDefaultValue($default);