Portals; New "Supports Session state" setting so the overhead of using Portal Session State can be disabled

The Portals form, General page has a new setting "Supports Session state".

This is checked by default for backwards compatibility but can be unchecked to avoid the overhead associated with maintaining Portal Session State (the ability to persist information between page calls for the current User/ Client).

Any attempt by a Portal Script to reference mPortalHandler.Session will result in a This Portal is not configured to support Session State. exception.