Issue #3149799 by mxr576, jungle: BasicAuth::authenticate() does not respect...

Issue #3149799 by mxr576, jungle: BasicAuth::authenticate() does not respect the implemented interface

(cherry picked from commit e884efa3)

core/modules/basic_auth/src/Authentication/Provider/BasicAuth.php

@@ -121,7 +121,7 @@ public function authenticate(Request $request) {
     }
     // Always register an IP-based failed login event.
     $this->flood->register('basic_auth.failed_login_ip', $flood_config->get('ip_window'));
-    return [];
+    return NULL;
   }
 
   /**