Fix CI

Author: TavoNiievez

tests/unit/Codeception/Module/RestTest.php

@@ -664,6 +664,7 @@ public function testRestExecute(string $configUrl, string $requestUrl, string $e
                     $content
                 ) use ($expectedFullUrl) {
                     \PHPUnit\Framework\Assert::assertSame($expectedFullUrl, $uri);
+                    return '';
                 })
             );