Add SupportDashboardActivity to secondary user home AI

Secondary users could not see the support preference in the
settings home screen because it was missing from the list of
whitelisted activities. This CL adds the SupportDashboardActivity
to the list so that secondary users can see it.

Test: Robotests still pass for SettingsGateway
Change-Id: Ia48dbd5b8d396c1bdf050c102fee0a5cd5300ed2