fix(security): Log failing strict cookie check

The error is silent otherwise and makes it very hard to debug on a
production system.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

lib/base.php

@@ -561,6 +561,7 @@ class OC {
 
 			// All other endpoints require the lax and the strict cookie
 			if (!$request->passesStrictCookieCheck()) {
+				logger('core')->warning('Request does not pass strict cookie check');
 				self::sendSameSiteCookies();
 				// Debug mode gets access to the resources without strict cookie
 				// due to the fact that the SabreDAV browser also lives there.