Update the card behavior of Low Storage slice

If used storage >= 85%, show low storage slice to all clients. Else, a
generic storage slice with error flag will be given. Home page will
check error flag in loading eligible cards.

Bug: 114808204
Test: robotests, visual
Change-Id: I757c46b3bbff785dc112fec6bdc37e5ce9269ed8
2 files changed