SSP-1978 Inject ApplicationContext into PortalPreAuthenticatedProcessingFilter

Avoids problems when initializing that class from the uP shell. In that
usage, PortalPreAuthenticatedProcessingFilter was (by way of its
collaborators) asking PortalApplicationContextLocator for the current
ApplicationContext, but the latter was still being initialized, which
PortalApplicationContextLocator believed to be an error.