Add edu for apps being stopped when PS is locked

Changes made to Setup intro screen and private space settings dislaimer
that apps are stopped when private space is locked.

Screenshots:
go/ss/8YFWtjjC5pzhyyd.png
go/ss/5pvvo4YodaSiGzr.png
b/343166731#comment4

Bug: 343166731
Test: Manual
Change-Id: I46db598e1e94e210d904ade8b6b0cf498960cc2a