Show full screen 'Free up space' for large screen devices

Uses Intent.FLAG_ACTIVITY_NEW_TASK to start the Activity
and it will shows in different Activity stack.
Then it shows full screen 'Free up space' for different
Activity stack.

Bug: 197703552
Test: manual
      Storage -> click 'Free up space'
Change-Id: I8ce16aa23438424d4990171449884755e36cf21d