Minor change of signature on_http_response (#7825)

Follow-up of https://github.com/FreshRSS/FreshRSS/pull/7824

app/Models/SimplePieResponse.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 final class FreshRSS_SimplePieResponse extends \SimplePie\File
 {
 	#[\Override]
-	protected function on_http_response($response = ''): void {
+	protected function on_http_response($response): void {
 		syslog(LOG_INFO, 'FreshRSS SimplePie GET ' . $this->get_status_code() . ' ' . \SimplePie\Misc::url_remove_credentials($this->get_final_requested_uri()));
 
 		if (in_array($this->get_status_code(), [429, 503], true)) {