[TECHNICAL-SUPPORT] LPS-50680 WSRP ProxyServlet should preserve certain headers like "Cache-Control"

https://issues.liferay.com/browse/LPS-50680

Hi Michael,

I've made the changes the way I've thought they should be like. I've an additional question. Now, we have this logic:

````java
		String cookie = (String)session.getAttribute(WebKeys.COOKIE);

		if (Validator.isNotNull(cookie)) {
			urlConnection.setRequestProperty(HttpHeaders.COOKIE, cookie);
		}
````
Though, "cookie" will always be "null", since the session contains values like:

````java
{
	MARKUP_SERVICE_10182_10638_http://localhost:8080/wsrp-portlet/wsdl/1a4f5831-740c-df35-599d-fc5363640bf8=com.liferay.portal.kernel.util.TransientValue@4deb4a9,
	COOKIE_10182_10638_http://localhost:8080/wsrp-portlet/wsdl/1a4f5831-740c-df35-599d-fc5363640bf8=JSESSIONID=B81E4B7CB9A2D7C0C885DAC8AA4078C8,
	WSRP_CONSUMER_MANAGERS=com.liferay.portal.kernel.util.TransientValue@3926c5be
}
````

Do you think we should adjust that part as well? Couldn't we use the "Cookie" header from the request instead?

Let me know if you have any concerns.

Regards,
Tibor