Always send a push identifier on UI initialization

server/src/main/java/com/vaadin/server/communication/UIInitHandler.java

@@ -287,9 +287,7 @@ public abstract class UIInitHandler extends SynchronizedRequestHandler {
             if (session.getConfiguration().isXsrfProtectionEnabled()) {
                 writer.write(getSecurityKeyUIDL(session));
             }
-            if (uI.getPushConfiguration().getPushMode().isEnabled()) {
-                writer.write(getPushIdUIDL(session));
-            }
+            writer.write(getPushIdUIDL(session));
             new UidlWriter().write(uI, writer, false);
             writer.write("}");