Fix validate error (#9700)

* Fix a couple install issues
validate failing too early caused an class not found error
return success in the db update output

* revert db-update changes, for separate PR

validate.php

@@ -65,6 +65,10 @@ register_shutdown_function(function () {
     global $precheck_complete;
 
     if (!$precheck_complete) {
+        // use this in case composer autoloader isn't available
+        spl_autoload_register(function($class) {
+            include str_replace('\\', '/', $class) . '.php';
+        });
         print_header(version_info());
     }
 });