[cts] Fix ResourcesHardeningTest for secondary users

Test used to install an app for the primary user only, but
then tried to get its context for the current one, effectively
breaking any runs as non-primary user.

Bug: 197564905
Test: atest --user-type secondary_user ResourcesHardeningTest
Change-Id: I81d0ee4214f1981d65788fd71a0801524cb60a0c
2 files changed