Remove "Danger" alert for users when session times out

Issue

In Liferay portal, when the session is inactive, the users are seeing "Danger: Due to inactivity your session timed out."

It is possible to disable the notification, by using the following property:
"session.timeout.warning=0" in the portal-ext.properties
To use the property:
- Specify the number of minutes before a warning is sent to the user informing the user of the session expiration. Specify 0 to disable any warnings.