Automatic session timeout redirects unreliable with websockets enabled

Steps to Reproduce

simple test zul

<zk>
	<label value="Session: ${session.nativeSession.id}, Desktop: ${desktop.id}"></label>
</zk>

enable automatic-session-timeout with a timeout-uri (configuring short timeout and redirect-loop make debugging easier)

	<session-config>
		<device-type>ajax</device-type>
		<timeout-uri>/test.zul</timeout-uri>
		<automatic-timeout>true</automatic-timeout>
		<session-timeout>10</session-timeout>
	</session-config>

Current Result

The automatic redirect doesn't always occur. Sometimes the page remains unchanged

Expected Result

Reliable redirect after timeout

Debug Info

As seen in automatic-session-timeout-with-ws.png the last WS request didn't disconnect after 10 seconds. Instead of a "/zkau" request containing the "dummy", the "dummy" was sent to the ws endpoint. ->Then session timeout handling doesnt happen