Do not special case the storage permission group.

We are now not showing storage usages in Permission Controller,
including in the API Settings uses.  We can thus remove this code so
that Settings will reflect what Permissions Hub shows.

Bug: 130567526
Test: See the same graph here and in the dashboard.
Change-Id: Iaa7d95b05f4321543ed42833ac3a7babdb9914f0