If set to true, the plugin validates the keycloak token after
the access token expires or on each request depending on the access
token configuration. This is necessary if you want to implement a
global/single sign out scenario with keycloak, because this plugin does
not support a back channel logout.
If set to false (default), the plugin only validates the
keycloak authentication at the beginning of the session. Afterwards no
validation takes place, so the user could log out in keycloak or the
access token could timeout in the meantime, but the user stays logged
in in jenkins. This will be true until the user logs out in jenkins or
the users session in jenkins times out.