chore: PHP 8.4 compat work. Implicitly marking parameter $x as nullable is...

chore: PHP 8.4 compat work. Implicitly marking parameter $x as nullable is deprecated, the explicit nullable type must be used instead.

css/oauth2-server-auth-dialog.css

@@ -15,6 +15,6 @@
   border-bottom: 1px dashed lightblue;
 }
 .oauth2-server--auth-dialog-header .check-mark {
-  background-repeat:no-repeat;
+  background-repeat: no-repeat;
   background-position: center center;
 }