Personal sounds override work sounds, not replace

To make it clear that the work choices will be preserved, and will be
restored after cancelling the setting instead of the personal sounds
being kept as-is.

Test: inspection (open sound settings, choose 'use personal profile sounds'). This is a strings change.
Bug: 34730524
Change-Id: I19953005d129000939fb3851148b2f837e2aa6c2