Fix DreamManagerService dream validation in HSUM

The current validation logic always checks the system user's
PackageManager state. We need to ensure we check if the component is
available for a particular user, not just the system user.

Fixes: 376042468
Test: manually on HSUM build
Flag: EXEMPT bugfix
Change-Id: I396d939ec827889dd21004887f64cc59d747ad7d