Fixed permisssions on setStopBackgroundUsersOnSwitch().

It was requiring INTERACT_ACROSS_USERS_FULL (instead of
INTERACT_ACROSS_USERS), which cannot be granted by Shell
(and hence cannot be used by CtsVerifier).

Test: m update-api
Test: manual verification
Bug: 203752848

Change-Id: Ie84311e6500cefa055548e309ee6d629c62fb10d
3 files changed