Allow subtext for all permissions groups

Previously subtext in the permission grant dialog was reserved
only for permission groups that had foreground/background
capabilities.

Test: Request MEDIA_VISUAL which will now have subtext
      Didn't observe subtext from other permission groups
          which previsouly didn't have subtext

Change-Id: Id09fc4eed95c4b21e0405a7c661d7bba5352030d