Update the API usage to get total size of devices

StorageStatsManager fixed in StorageStatsService#getTotalBytes
So that we should change back to call the API.

Bug: 295358118
Bug: 288103116
Test: verified manually
Change-Id: I3dcc9698403612f961cf0de41925dcbcb43e260b
(cherry picked from commit 2d57d002)