Fix InstantAppRegistry for secondary users.

This changes adds an initialization in PackageManagerService
constructor for per-user Instant App list in InstantAppRegistry so
that the list is initialized for all users. It also fixes callers
passing uid instead of app id when calling grantEphemeralAccess().

Bug: 111370050
Bug: 111436542
Test: cl/209819423
Change-Id: I42c72188365dd67e903f80a1c1e425124f0db241