Merge work profile storage data together

- Storage UI used to have a work profile item. Now the item is
removed, all its size should merge to other item.

Fixes: 147127503
Test: Add work profile user, in Settings -> Storage page. Sum of
each item size should be similar to used size in the top of the page.

Change-Id: I9d4e2c8c53839da22fd0cdd5d2591a3245514191